/*
 * YAFFS: Yet Another Flash File System. A NAND-flash specific file system.
 *
 * Copyright (C) 2002-2011 Aleph One Ltd.
 *   for Toby Churchill Ltd and Brightstar Engineering
 *
 * Created by Charles Manning <charles@aleph1.co.uk>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include "yportenv.h"
#include "yaffs_trace.h"
#include "yaffs_guts.h"
#include "yaffs_getblockinfo.h"
#include "yaffs_tagscompat.h"
#include "yaffs_nand.h"
#include "yaffs_yaffs1.h"
#include "yaffs_yaffs2.h"
#include "yaffs_bitmap.h"
#include "yaffs_verify.h"
#include "yaffs_nand.h"
#include "yaffs_packedtags2.h"
#include "yaffs_nameval.h"
#include "yaffs_allocator.h"
#include "yaffs_attribs.h"
#include "yaffs_summary.h"

//DEFY
#include "yaffs_defy.h"

/* Note YAFFS_GC_GOOD_ENOUGH must be <= YAFFS_GC_PASSIVE_THRESHOLD */
#define YAFFS_GC_GOOD_ENOUGH 2
#define YAFFS_GC_PASSIVE_THRESHOLD 4

#include "yaffs_ecc.h"

/* Forward declarations */

static int yaffs_wr_data_obj(struct yaffs_obj *in, int inode_chunk,
			     const u8 *buffer, int n_bytes, int use_reserve);



/* Function to calculate chunk and offset */

static inline void yaffs_addr_to_chunk(struct yaffs_dev *dev, loff_t addr,
				       int *chunk_out, u32 *offset_out)
{
    int chunk;
    u32 offset;

    chunk = (u32) (addr >> dev->chunk_shift);

    if (dev->chunk_div == 1) {
	/* easy power of 2 case */
	offset = (u32) (addr & dev->chunk_mask);
    } else {
	/* Non power-of-2 case */

	loff_t chunk_base;

	chunk /= dev->chunk_div;

	chunk_base = ((loff_t) chunk) * dev->data_bytes_per_chunk;
	offset = (u32) (addr - chunk_base);
    }

    *chunk_out = chunk;
    *offset_out = offset;
}

/* Function to return the number of shifts for a power of 2 greater than or
 * equal to the given number
 * Note we don't try to cater for all possible numbers and this does not have to
 * be hellishly efficient.
 */

static inline u32 calc_shifts_ceiling(u32 x)
{
    int extra_bits;
    int shifts;

    shifts = extra_bits = 0;

    while (x > 1) {
	if (x & 1)
	    extra_bits++;
	x >>= 1;
	shifts++;
    }

    if (extra_bits)
	shifts++;

    return shifts;
}

/* Function to return the number of shifts to get a 1 in bit 0
 */

static inline u32 calc_shifts(u32 x)
{
    u32 shifts;

    shifts = 0;

    if (!x)
	return 0;

    while (!(x & 1)) {
	x >>= 1;
	shifts++;
    }

    return shifts;
}

/*
 * Temporary buffer manipulations.
 */

static int yaffs_init_tmp_buffers(struct yaffs_dev *dev)
{
    int i;
    u8 *buf = (u8 *) 1;

    memset(dev->temp_buffer, 0, sizeof(dev->temp_buffer));

    for (i = 0; buf && i < YAFFS_N_TEMP_BUFFERS; i++) {
	dev->temp_buffer[i].in_use = 0;
	buf = kmalloc(dev->param.total_bytes_per_chunk, GFP_NOFS);
	dev->temp_buffer[i].buffer = buf;
    }

    return buf ? YAFFS_OK : YAFFS_FAIL;
}

u8 *yaffs_get_temp_buffer(struct yaffs_dev * dev)
{
    int i;

    dev->temp_in_use++;
    if (dev->temp_in_use > dev->max_temp)
	dev->max_temp = dev->temp_in_use;

    for (i = 0; i < YAFFS_N_TEMP_BUFFERS; i++) {
	if (dev->temp_buffer[i].in_use == 0) {
	    dev->temp_buffer[i].in_use = 1;
	    return dev->temp_buffer[i].buffer;
	}
    }

    yaffs_trace(YAFFS_TRACE_BUFFERS, "Out of temp buffers");
    /*
     * If we got here then we have to allocate an unmanaged one
     * This is not good.
     */

    dev->unmanaged_buffer_allocs++;
    return kmalloc(dev->data_bytes_per_chunk, GFP_NOFS);

}

void yaffs_release_temp_buffer(struct yaffs_dev *dev, u8 *buffer)
{
    int i;

    dev->temp_in_use--;

    for (i = 0; i < YAFFS_N_TEMP_BUFFERS; i++) {
	if (dev->temp_buffer[i].buffer == buffer) {
	    dev->temp_buffer[i].in_use = 0;
	    return;
	}
    }

    if (buffer) {
	/* assume it is an unmanaged one. */
	yaffs_trace(YAFFS_TRACE_BUFFERS, "Releasing unmanaged temp buffer");
	kfree(buffer);
	dev->unmanaged_buffer_deallocs++;
    }

}

/*
 * Determine if we have a managed buffer.
 */
int yaffs_is_managed_tmp_buffer(struct yaffs_dev *dev, const u8 *buffer)
{
    int i;

    for (i = 0; i < YAFFS_N_TEMP_BUFFERS; i++) {
	if (dev->temp_buffer[i].buffer == buffer)
	    return 1;
    }

    for (i = 0; i < dev->param.n_caches; i++) {
	if (dev->cache[i].data == buffer)
	    return 1;
    }

    if (buffer == dev->checkpt_buffer)
	return 1;

    yaffs_trace(YAFFS_TRACE_ALWAYS,
		"yaffs: unmaged buffer detected.");
    return 0;
}

/*
 * Functions for robustisizing TODO
 *
 */

static void yaffs_handle_chunk_wr_ok(struct yaffs_dev *dev, int nand_chunk,
				     const u8 *data,
				     const struct yaffs_ext_tags *tags)
{
    dev = dev;
    nand_chunk = nand_chunk;
    data = data;
    tags = tags;
}

static void yaffs_handle_chunk_update(struct yaffs_dev *dev, int nand_chunk,
				      const struct yaffs_ext_tags *tags)
{
    dev = dev;
    nand_chunk = nand_chunk;
    tags = tags;
}

void yaffs_handle_chunk_error(struct yaffs_dev *dev,
			      struct yaffs_block_info *bi)
{
    if (!bi->gc_prioritise) {
	bi->gc_prioritise = 1;
	dev->has_pending_prioritised_gc = 1;
	bi->chunk_error_strikes++;

	if (bi->chunk_error_strikes > 3) {
	    bi->needs_retiring = 1;	/* Too many stikes, so retire */
	    yaffs_trace(YAFFS_TRACE_ALWAYS,
			"yaffs: Block struck out");

	}
    }
}

static void yaffs_handle_chunk_wr_error(struct yaffs_dev *dev, int nand_chunk,
					int erased_ok)
{
    int flash_block = nand_chunk / dev->param.chunks_per_block;
    struct yaffs_block_info *bi = yaffs_get_block_info(dev, flash_block);

    yaffs_handle_chunk_error(dev, bi);

    if (erased_ok) {
	/* Was an actual write failure,
	 * so mark the block for retirement.*/
	bi->needs_retiring = 1;
	yaffs_trace(YAFFS_TRACE_ERROR | YAFFS_TRACE_BAD_BLOCKS,
		    "**>> Block %d needs retiring", flash_block);
    }

    /* Delete the chunk */
    yaffs_chunk_del(dev, nand_chunk, 1, __LINE__);
    yaffs_skip_rest_of_block(dev);
}

/*
 * Verification code
 */

/*
 *  Simple hash function. Needs to have a reasonable spread
 */

static inline int yaffs_hash_fn(int n)
{
    n = abs(n);
    return n % YAFFS_NOBJECT_BUCKETS;
}

/*
 * Access functions to useful fake objects.
 * Note that root might have a presence in NAND if permissions are set.
 */

struct yaffs_obj *yaffs_root(struct yaffs_dev *dev)
{
    return dev->root_dir;
}

struct yaffs_obj *yaffs_lost_n_found(struct yaffs_dev *dev)
{
    return dev->lost_n_found;
}

/*
 *  Erased NAND checking functions
 */

int yaffs_check_ff(u8 *buffer, int n_bytes)
{
    /* Horrible, slow implementation */
    while (n_bytes--) {
	if (*buffer != 0xff)
	    return 0;
	buffer++;
    }
    return 1;
}

static int yaffs_check_chunk_erased(struct yaffs_dev *dev, int nand_chunk)
{
    int retval = YAFFS_OK;
    u8 *data = yaffs_get_temp_buffer(dev);
    struct yaffs_ext_tags tags;
    int result;

    // DEFY: Don't try to decrypt an erased chunk
    tags.defy_level = -1;
    result = yaffs_rd_chunk_tags_nand(dev, nand_chunk, data, &tags);

    if (tags.ecc_result > YAFFS_ECC_RESULT_NO_ERROR)
	retval = YAFFS_FAIL;

    if (!yaffs_check_ff(data, dev->data_bytes_per_chunk) ||
	tags.chunk_used) {
	yaffs_trace(YAFFS_TRACE_NANDACCESS,
		    "Chunk %d not erased", nand_chunk);
	retval = YAFFS_FAIL;
    }

    yaffs_release_temp_buffer(dev, data);

    return retval;

}

static int yaffs_verify_chunk_written(struct yaffs_dev *dev,
				      int nand_chunk,
				      const u8 *data,
				      struct yaffs_ext_tags *tags)
{
    int retval = YAFFS_OK;
    struct yaffs_ext_tags temp_tags;
    u8 *buffer = yaffs_get_temp_buffer(dev);
    int result;

    result = yaffs_rd_chunk_tags_nand(dev, nand_chunk, buffer, &temp_tags);

    if (memcmp(buffer, data, dev->data_bytes_per_chunk) ||
	temp_tags.obj_id != tags->obj_id ||
	temp_tags.chunk_id != tags->chunk_id ||
	temp_tags.n_bytes != tags->n_bytes)
	retval = YAFFS_FAIL;

    yaffs_release_temp_buffer(dev, buffer);

    return retval;
}


int yaffs_check_alloc_available(struct yaffs_dev *dev, int n_chunks)
{
    int reserved_chunks;
    int reserved_blocks = dev->param.n_reserved_blocks;
    int checkpt_blocks;

    checkpt_blocks = yaffs_calc_checkpt_blocks_required(dev);

    reserved_chunks =
	(reserved_blocks + checkpt_blocks) * dev->param.chunks_per_block;
    //defy_printk_indent();
    //printk("There are %d free chunks\n", dev->n_free_chunks);
    return (dev->n_free_chunks > (reserved_chunks + n_chunks));
}

static int yaffs_find_alloc_block(struct yaffs_dev *dev)
{
    int i;
    struct yaffs_block_info *bi;

    if (dev->n_erased_blocks < 1) {
	/* Hoosterman we've got a problem.
	 * Can't get space to gc
	 */
	yaffs_trace(YAFFS_TRACE_ERROR,
		    "yaffs tragedy: no more erased blocks");

	return -1;
    }

    //defy_printk("yaffs_find_alloc_block", BEGIN_F);
    /* Find an empty block. */

    for (i = dev->internal_start_block; i <= dev->internal_end_block; i++) {
	dev->alloc_block_finder++;
	if (dev->alloc_block_finder < dev->internal_start_block
	    || dev->alloc_block_finder > dev->internal_end_block) {
	    dev->alloc_block_finder = dev->internal_start_block;
	}

	bi = yaffs_get_block_info(dev, dev->alloc_block_finder);

	if (bi->block_state == YAFFS_BLOCK_STATE_EMPTY) {
	    bi->block_state = YAFFS_BLOCK_STATE_ALLOCATING;
	    dev->seq_number++;
	    bi->seq_number = dev->seq_number;
	    yaffs_trace(YAFFS_TRACE_ALLOCATE,
			"Allocated block %d, seq  %d, %d left" ,
			dev->alloc_block_finder, dev->seq_number,
			dev->n_erased_blocks);
	    //defy_printk_indent();
	    //printk("Allocated block %d\n", dev->alloc_block_finder);
	    //defy_printk_indent();
	    //printk("New seq_number is %d\n", dev->seq_number);
	    //defy_printk("yaffs_find_alloc_block", END_F);
	    return dev->alloc_block_finder;
	}
    }

    yaffs_trace(YAFFS_TRACE_ALWAYS,
		"yaffs tragedy: no more erased blocks, but there should have been %d",
		dev->n_erased_blocks);

    return -1;
}

static int yaffs_alloc_chunk(struct yaffs_dev *dev, int use_reserver,
			     struct yaffs_block_info **block_ptr)
{
    int ret_val;
    struct yaffs_block_info *bi;

    if (dev->alloc_block < 0) {
	/* Get next block to allocate off */
	dev->alloc_block = yaffs_find_alloc_block(dev);
	dev->alloc_page = 0;
    }

    if (!use_reserver && !yaffs_check_alloc_available(dev, 1)) {
	/* No space unless we're allowed to use the reserve. */
	defy_printk("No space!", IN_F);
	return -1;
    }

    if (dev->n_erased_blocks < dev->param.n_reserved_blocks
	&& dev->alloc_page == 0)
	yaffs_trace(YAFFS_TRACE_ALLOCATE, "Allocating reserve");

    /* Next page please.... */
    if (dev->alloc_block >= 0) {
	bi = yaffs_get_block_info(dev, dev->alloc_block);

	ret_val = (dev->alloc_block * dev->param.chunks_per_block) +
	    dev->alloc_page;
	bi->pages_in_use++;
	//defy_printk_indent();
	//printk("Allocated chunk %d in block %d\n", ret_val, dev->alloc_block);
	//defy_printk_indent();
	//printk("alloc_block %d, page %d\n", dev->alloc_block, dev->alloc_page);
	yaffs_set_chunk_bit(dev, dev->alloc_block, dev->alloc_page);

	dev->alloc_page++;

	// DEFY: We manage free chunks elsewhere
	//dev->n_free_chunks--;

	/* If the block is full set the state to full */
	if (dev->alloc_page >= dev->param.chunks_per_block) {
	    bi->block_state = YAFFS_BLOCK_STATE_FULL;
	    dev->alloc_block = -1;
	}

	if (block_ptr)
	    *block_ptr = bi;

	return ret_val;
    }

    yaffs_trace(YAFFS_TRACE_ERROR,
		"!!!!!!!!! Allocator out !!!!!!!!!!!!!!!!!");

    return -1;
}

static int yaffs_get_erased_chunks(struct yaffs_dev *dev)
{
    int n;

    n = dev->n_erased_blocks * dev->param.chunks_per_block;

    if (dev->alloc_block > 0)
	n += (dev->param.chunks_per_block - dev->alloc_page);

    return n;

}

/*
 * yaffs_skip_rest_of_block() skips over the rest of the allocation block
 * if we don't want to write to it.
 */
void yaffs_skip_rest_of_block(struct yaffs_dev *dev)
{
    struct yaffs_block_info *bi;

    if (dev->alloc_block > 0) {
	bi = yaffs_get_block_info(dev, dev->alloc_block);
	if (bi->block_state == YAFFS_BLOCK_STATE_ALLOCATING) {
	    bi->block_state = YAFFS_BLOCK_STATE_FULL;
	    dev->alloc_block = -1;
	}
    }
}

static int yaffs_write_new_chunk(struct yaffs_dev *dev,
				 const u8 *data,
				 struct yaffs_ext_tags *tags, int use_reserver)
{
    int attempts = 0;
    int write_ok = 0;
    int chunk;

    //defy_printk("yaffs_write_new_chunk", BEGIN_F);

    yaffs2_checkpt_invalidate(dev);

    do {
	struct yaffs_block_info *bi = 0;
	int erased_ok = 0;

	chunk = yaffs_alloc_chunk(dev, use_reserver, &bi);
	if (chunk < 0) {
	    /* no space */
	    break;
	}

	/* First check this chunk is erased, if it needs
	 * checking.  The checking policy (unless forced
	 * always on) is as follows:
	 *
	 * Check the first page we try to write in a block.
	 * If the check passes then we don't need to check any
	 * more.        If the check fails, we check again...
	 * If the block has been erased, we don't need to check.
	 *
	 * However, if the block has been prioritised for gc,
	 * then we think there might be something odd about
	 * this block and stop using it.
	 *
	 * Rationale: We should only ever see chunks that have
	 * not been erased if there was a partially written
	 * chunk due to power loss.  This checking policy should
	 * catch that case with very few checks and thus save a
	 * lot of checks that are most likely not needed.
	 *
	 * Mods to the above
	 * If an erase check fails or the write fails we skip the
	 * rest of the block.
	 */

	/* let's give it a try */
	attempts++;

	if (dev->param.always_check_erased)
	    bi->skip_erased_check = 0;
	// DEFY: A block will never be erased
	bi->skip_erased_check = 1;

	if (!bi->skip_erased_check) {
	    erased_ok = yaffs_check_chunk_erased(dev, chunk);
	    if (erased_ok != YAFFS_OK) {
		yaffs_trace(YAFFS_TRACE_ERROR,
			    "**>> yaffs chunk %d was not erased",
			    chunk);

		/* If not erased, delete this one,
		 * skip rest of block and
		 * try another chunk */
		yaffs_chunk_del(dev, chunk, 1, __LINE__);
		yaffs_skip_rest_of_block(dev);
		continue;
	    }
	}

	write_ok = yaffs_wr_chunk_tags_nand(dev, chunk, data, tags);
	if(tags) {
	    //defy_printk_indent();
	    //printk("write_new_chunk at level %d\n", tags->defy_level);
	}

	if (!bi->skip_erased_check)
	    write_ok =
		yaffs_verify_chunk_written(dev, chunk, data, tags);

	if (write_ok != YAFFS_OK) {
	    /* Clean up aborted write, skip to next block and
	     * try another chunk */
	    yaffs_handle_chunk_wr_error(dev, chunk, erased_ok);
	    continue;
	}

	bi->skip_erased_check = 1;

	/* Copy the data into the robustification buffer */
	yaffs_handle_chunk_wr_ok(dev, chunk, data, tags);

    } while (write_ok != YAFFS_OK &&
	     (yaffs_wr_attempts <= 0 || attempts <= yaffs_wr_attempts));

    if (!write_ok)
	chunk = -1;

    if (attempts > 1) {
	yaffs_trace(YAFFS_TRACE_ERROR,
		    "**>> yaffs write required %d attempts",
		    attempts);
	dev->n_retried_writes += (attempts - 1);
    }

    //defy_printk("yaffs_write_new_chunk", END_F);

    return chunk;
}

// DEFY: DEFY hook into writing chunks
int defy_write_new_chunk(struct yaffs_dev *dev, const u8 *data,
			 struct yaffs_ext_tags *tags, int use_reserver) {
    return yaffs_write_new_chunk(dev, data, tags, use_reserver);
}

/*
 * Block retiring for handling a broken block.
 */

static void yaffs_retire_block(struct yaffs_dev *dev, int flash_block)
{
    struct yaffs_block_info *bi = yaffs_get_block_info(dev, flash_block);

    yaffs2_checkpt_invalidate(dev);

    yaffs2_clear_oldest_dirty_seq(dev, bi);

    if (yaffs_mark_bad(dev, flash_block) != YAFFS_OK) {
	if (yaffs_erase_block(dev, flash_block) != YAFFS_OK) {
	    yaffs_trace(YAFFS_TRACE_ALWAYS,
			"yaffs: Failed to mark bad and erase block %d",
			flash_block);
	} else {
	    struct yaffs_ext_tags tags;
	    int chunk_id =
		flash_block * dev->param.chunks_per_block;

	    u8 *buffer = yaffs_get_temp_buffer(dev);

	    memset(buffer, 0xff, dev->data_bytes_per_chunk);
	    memset(&tags, 0, sizeof(tags));
	    tags.seq_number = YAFFS_SEQUENCE_BAD_BLOCK;
	    if (dev->param.write_chunk_tags_fn(dev, chunk_id -
					       dev->chunk_offset,
					       buffer,
					       &tags) != YAFFS_OK)
		yaffs_trace(YAFFS_TRACE_ALWAYS,
			    "yaffs: Failed to write bad block marker to block %d",
			    flash_block);

	    yaffs_release_temp_buffer(dev, buffer);
	}
    }

    bi->block_state = YAFFS_BLOCK_STATE_DEAD;
    bi->gc_prioritise = 0;
    bi->needs_retiring = 0;

    dev->n_retired_blocks++;
}

/*---------------- Name handling functions ------------*/

static u16 yaffs_calc_name_sum(const YCHAR *name)
{
    u16 sum = 0;
    u16 i = 1;

    if (!name)
	return 0;

    while ((*name) && i < (YAFFS_MAX_NAME_LENGTH / 2)) {

	/* 0x1f mask is case insensitive */
	sum += ((*name) & 0x1f) * i;
	i++;
	name++;
    }
    return sum;
}

void yaffs_set_obj_name(struct yaffs_obj *obj, const YCHAR * name)
{
    memset(obj->short_name, 0, sizeof(obj->short_name));
    if (name &&
	strnlen(name, YAFFS_SHORT_NAME_LENGTH + 1) <=
	YAFFS_SHORT_NAME_LENGTH)
	strcpy(obj->short_name, name);
    else
	obj->short_name[0] = _Y('\0');
    obj->sum = yaffs_calc_name_sum(name);
}

void yaffs_set_obj_name_from_oh(struct yaffs_obj *obj,
				const struct yaffs_obj_hdr *oh)
{
#ifdef CONFIG_YAFFS_AUTO_UNICODE
    YCHAR tmp_name[YAFFS_MAX_NAME_LENGTH + 1];
    memset(tmp_name, 0, sizeof(tmp_name));
    yaffs_load_name_from_oh(obj->my_dev, tmp_name, oh->name,
			    YAFFS_MAX_NAME_LENGTH + 1);
    yaffs_set_obj_name(obj, tmp_name);
#else
    yaffs_set_obj_name(obj, oh->name);
#endif
}

/*-------------------- TNODES -------------------

 * List of spare tnodes
 * The list is hooked together using the first pointer
 * in the tnode.
 */

struct yaffs_tnode *yaffs_get_tnode(struct yaffs_dev *dev)
{
    struct yaffs_tnode *tn = yaffs_alloc_raw_tnode(dev);

    if (tn) {
	memset(tn, 0, dev->tnode_size);
	dev->n_tnodes++;
    }

    dev->checkpoint_blocks_required = 0;	/* force recalculation */

    return tn;
}

/* FreeTnode frees up a tnode and puts it back on the free list */
static void yaffs_free_tnode(struct yaffs_dev *dev, struct yaffs_tnode *tn)
{
    yaffs_free_raw_tnode(dev, tn);
    dev->n_tnodes--;
    dev->checkpoint_blocks_required = 0;	/* force recalculation */
}

static void yaffs_deinit_tnodes_and_objs(struct yaffs_dev *dev)
{
    yaffs_deinit_raw_tnodes_and_objs(dev);
    dev->n_obj = 0;
    dev->n_tnodes = 0;
}

void yaffs_load_tnode_0(struct yaffs_dev *dev, struct yaffs_tnode *tn,
			unsigned pos, unsigned val)
{
    u32 *map = (u32 *) tn;
    u32 bit_in_map;
    u32 bit_in_word;
    u32 word_in_map;
    u32 mask;

    pos &= YAFFS_TNODES_LEVEL0_MASK;
    val >>= dev->chunk_grp_bits;

    bit_in_map = pos * dev->tnode_width;
    word_in_map = bit_in_map / 32;
    bit_in_word = bit_in_map & (32 - 1);

    mask = dev->tnode_mask << bit_in_word;

    map[word_in_map] &= ~mask;
    map[word_in_map] |= (mask & (val << bit_in_word));

    if (dev->tnode_width > (32 - bit_in_word)) {
	bit_in_word = (32 - bit_in_word);
	word_in_map++;
	mask =
	    dev->tnode_mask >> bit_in_word;
	map[word_in_map] &= ~mask;
	map[word_in_map] |= (mask & (val >> bit_in_word));
    }
}

u32 yaffs_get_group_base(struct yaffs_dev *dev, struct yaffs_tnode *tn,
			 unsigned pos)
{
    u32 *map = (u32 *) tn;
    u32 bit_in_map;
    u32 bit_in_word;
    u32 word_in_map;
    u32 val;

    pos &= YAFFS_TNODES_LEVEL0_MASK;

    bit_in_map = pos * dev->tnode_width;
    word_in_map = bit_in_map / 32;
    bit_in_word = bit_in_map & (32 - 1);

    val = map[word_in_map] >> bit_in_word;

    if (dev->tnode_width > (32 - bit_in_word)) {
	bit_in_word = (32 - bit_in_word);
	word_in_map++;
	val |= (map[word_in_map] << bit_in_word);
    }

    val &= dev->tnode_mask;
    val <<= dev->chunk_grp_bits;

    return val;
}

/* ------------------- End of individual tnode manipulation -----------------*/

/* ---------Functions to manipulate the look-up tree (made up of tnodes) ------
 * The look up tree is represented by the top tnode and the number of top_level
 * in the tree. 0 means only the level 0 tnode is in the tree.
 */

/* FindLevel0Tnode finds the level 0 tnode, if one exists. */
struct yaffs_tnode *yaffs_find_tnode_0(struct yaffs_dev *dev,
				       struct yaffs_file_var *file_struct,
				       u32 chunk_id)
{
    struct yaffs_tnode *tn = file_struct->top;
    u32 i;
    int required_depth;
    int level = file_struct->top_level;

    dev = dev;

    /* Check sane level and chunk Id */
    if (level < 0 || level > YAFFS_TNODES_MAX_LEVEL)
	return NULL;

    if (chunk_id > YAFFS_MAX_CHUNK_ID)
	return NULL;

    /* First check we're tall enough (ie enough top_level) */

    i = chunk_id >> YAFFS_TNODES_LEVEL0_BITS;
    required_depth = 0;
    while (i) {
	i >>= YAFFS_TNODES_INTERNAL_BITS;
	required_depth++;
    }

    if (required_depth > file_struct->top_level)
	return NULL;	/* Not tall enough, so we can't find it */

    /* Traverse down to level 0 */
    while (level > 0 && tn) {
	tn = tn->internal[(chunk_id >>
			   (YAFFS_TNODES_LEVEL0_BITS +
			    (level - 1) *
			    YAFFS_TNODES_INTERNAL_BITS)) &
			  YAFFS_TNODES_INTERNAL_MASK];
	level--;
    }

    return tn;
}

/* add_find_tnode_0 finds the level 0 tnode if it exists,
 * otherwise first expands the tree.
 * This happens in two steps:
 *  1. If the tree isn't tall enough, then make it taller.
 *  2. Scan down the tree towards the level 0 tnode adding tnodes if required.
 *
 * Used when modifying the tree.
 *
 *  If the tn argument is NULL, then a fresh tnode will be added otherwise the
 *  specified tn will be plugged into the ttree.
 */

struct yaffs_tnode *yaffs_add_find_tnode_0(struct yaffs_dev *dev,
					   struct yaffs_file_var *file_struct,
					   u32 chunk_id,
					   struct yaffs_tnode *passed_tn)
{
    int required_depth;
    int i;
    int l;
    struct yaffs_tnode *tn;
    u32 x;

    /* Check sane level and page Id */
    if (file_struct->top_level < 0 ||
	file_struct->top_level > YAFFS_TNODES_MAX_LEVEL)
	return NULL;

    if (chunk_id > YAFFS_MAX_CHUNK_ID)
	return NULL;

    /* First check we're tall enough (ie enough top_level) */

    x = chunk_id >> YAFFS_TNODES_LEVEL0_BITS;
    required_depth = 0;
    while (x) {
	x >>= YAFFS_TNODES_INTERNAL_BITS;
	required_depth++;
    }

    if (required_depth > file_struct->top_level) {
	/* Not tall enough, gotta make the tree taller */
	for (i = file_struct->top_level; i < required_depth; i++) {

	    tn = yaffs_get_tnode(dev);

	    if (tn) {
		tn->internal[0] = file_struct->top;
		file_struct->top = tn;
		file_struct->top_level++;
	    } else {
		yaffs_trace(YAFFS_TRACE_ERROR,
			    "yaffs: no more tnodes");
		return NULL;
	    }
	}
    }

    /* Traverse down to level 0, adding anything we need */

    l = file_struct->top_level;
    tn = file_struct->top;

    if (l > 0) {
	while (l > 0 && tn) {
	    x = (chunk_id >>
		 (YAFFS_TNODES_LEVEL0_BITS +
		  (l - 1) * YAFFS_TNODES_INTERNAL_BITS)) &
		YAFFS_TNODES_INTERNAL_MASK;

	    if ((l > 1) && !tn->internal[x]) {
		/* Add missing non-level-zero tnode */
		tn->internal[x] = yaffs_get_tnode(dev);
		if (!tn->internal[x])
		    return NULL;
	    } else if (l == 1) {
		/* Looking from level 1 at level 0 */
		if (passed_tn) {
		    /* If we already have one, release it */
		    if (tn->internal[x])
			yaffs_free_tnode(dev,
					 tn->internal[x]);
		    tn->internal[x] = passed_tn;

		} else if (!tn->internal[x]) {
		    /* Don't have one, none passed in */
		    tn->internal[x] = yaffs_get_tnode(dev);
		    if (!tn->internal[x])
			return NULL;
		}
	    }

	    tn = tn->internal[x];
	    l--;
	}
    } else {
	/* top is level 0 */
	if (passed_tn) {
	    memcpy(tn, passed_tn,
		   (dev->tnode_width * YAFFS_NTNODES_LEVEL0) / 8);
	    yaffs_free_tnode(dev, passed_tn);
	}
    }

    return tn;
}

static int yaffs_tags_match(const struct yaffs_ext_tags *tags, int obj_id,
			    int chunk_obj)
{
    return (tags->chunk_id == chunk_obj &&
	    tags->obj_id == obj_id &&
	    !tags->is_deleted) ? 1 : 0;

}

static int yaffs_find_chunk_in_group(struct yaffs_dev *dev, int the_chunk,
				     struct yaffs_ext_tags *tags, int obj_id,
				     int inode_chunk)
{
    int j;

    for (j = 0; the_chunk && j < dev->chunk_grp_size; j++) {
	if (yaffs_check_chunk_bit
	    (dev, the_chunk / dev->param.chunks_per_block,
	     the_chunk % dev->param.chunks_per_block)) {

	    if (dev->chunk_grp_size == 1)
		return the_chunk;
	    else {
		yaffs_rd_chunk_tags_nand(dev, the_chunk, NULL,
					 tags);
		if (yaffs_tags_match(tags,
				     obj_id, inode_chunk)) {
		    /* found it; */
		    return the_chunk;
		}
	    }
	}
	the_chunk++;
    }
    return -1;
}

static int yaffs_find_chunk_in_file(struct yaffs_obj *in, int inode_chunk,
				    struct yaffs_ext_tags *tags)
{
    /*Get the Tnode, then get the level 0 offset chunk offset */
    struct yaffs_tnode *tn;
    int the_chunk = -1;
    struct yaffs_ext_tags local_tags;
    int ret_val = -1;
    struct yaffs_dev *dev = in->my_dev;

    if (!tags) {
	/* Passed a NULL, so use our own tags space */
	tags = &local_tags;
    }

    tn = yaffs_find_tnode_0(dev, &in->variant.file_variant, inode_chunk);

    if (!tn)
	return ret_val;

    the_chunk = yaffs_get_group_base(dev, tn, inode_chunk);

    // DEFY: set tags level
    tags->defy_level = in->defy_level;

    ret_val = yaffs_find_chunk_in_group(dev, the_chunk, tags, in->obj_id,
					inode_chunk);
    return ret_val;
}

static int yaffs_find_del_file_chunk(struct yaffs_obj *in, int inode_chunk,
				     struct yaffs_ext_tags *tags)
{
    /* Get the Tnode, then get the level 0 offset chunk offset */
    struct yaffs_tnode *tn;
    int the_chunk = -1;
    struct yaffs_ext_tags local_tags;
    struct yaffs_dev *dev = in->my_dev;
    int ret_val = -1;

    if (!tags) {
	/* Passed a NULL, so use our own tags space */
	tags = &local_tags;
    }

    tn = yaffs_find_tnode_0(dev, &in->variant.file_variant, inode_chunk);

    if (!tn)
	return ret_val;

    the_chunk = yaffs_get_group_base(dev, tn, inode_chunk);

    // DEFY: set tags level
    tags->defy_level = in->defy_level;

    ret_val = yaffs_find_chunk_in_group(dev, the_chunk, tags, in->obj_id,
					inode_chunk);

    /* Delete the entry in the filestructure (if found) */
    if (ret_val != -1)
	yaffs_load_tnode_0(dev, tn, inode_chunk, 0);

    return ret_val;
}

int yaffs_put_chunk_in_file(struct yaffs_obj *in, int inode_chunk,
			    int nand_chunk, int in_scan)
{
    /* NB in_scan is zero unless scanning.
     * For forward scanning, in_scan is > 0;
     * for backward scanning in_scan is < 0
     *
     * nand_chunk = 0 is a dummy insert to make sure the tnodes are there.
     */

    struct yaffs_tnode *tn;
    struct yaffs_dev *dev = in->my_dev;
    int existing_cunk;
    struct yaffs_ext_tags existing_tags;
    struct yaffs_ext_tags new_tags;
    unsigned existing_serial, new_serial;

    if (in->variant_type != YAFFS_OBJECT_TYPE_FILE) {
	/* Just ignore an attempt at putting a chunk into a non-file
	 * during scanning.
	 * If it is not during Scanning then something went wrong!
	 */
	if (!in_scan) {
	    yaffs_trace(YAFFS_TRACE_ERROR,
			"yaffs tragedy:attempt to put data chunk into a non-file"
			);
	    BUG();
	}

	yaffs_chunk_del(dev, nand_chunk, 1, __LINE__);
	return YAFFS_OK;
    }

    tn = yaffs_add_find_tnode_0(dev,
				&in->variant.file_variant,
				inode_chunk, NULL);
    if (!tn)
	return YAFFS_FAIL;

    if (!nand_chunk)
	/* Dummy insert, bail now */
	return YAFFS_OK;

    existing_cunk = yaffs_get_group_base(dev, tn, inode_chunk);

    if (in_scan != 0) {
	/* If we're scanning then we need to test for duplicates
	 * NB This does not need to be efficient since it should only
	 * happen when the power fails during a write, then only one
	 * chunk should ever be affected.
	 *
	 * Correction for YAFFS2: This could happen quite a lot and we
	 * need to think about efficiency! TODO
	 * Update: For backward scanning we don't need to re-read tags
	 * so this is quite cheap.
	 */

	if (existing_cunk > 0) {
	    /* NB Right now existing chunk will not be real
	     * chunk_id if the chunk group size > 1
	     * thus we have to do a FindChunkInFile to get the
	     * real chunk id.
	     *
	     * We have a duplicate now we need to decide which
	     * one to use:
	     *
	     * Backwards scanning YAFFS2: The old one is what
	     * we use, dump the new one.
	     * YAFFS1: Get both sets of tags and compare serial
	     * numbers.
	     */

	    if (in_scan > 0) {
		/* Only do this for forward scanning */
		// DEFY: set tags level
		new_tags.defy_level = in->defy_level;
		existing_tags.defy_level = in->defy_level;

		yaffs_rd_chunk_tags_nand(dev,
					 nand_chunk,
					 NULL, &new_tags);

		/* Do a proper find */
		existing_cunk =
		    yaffs_find_chunk_in_file(in, inode_chunk,
					     &existing_tags);
	    }

	    if (existing_cunk <= 0) {
		/*Hoosterman - how did this happen? */

		yaffs_trace(YAFFS_TRACE_ERROR,
			    "yaffs tragedy: existing chunk < 0 in scan"
			    );

	    }

	    /* NB The deleted flags should be false, otherwise
	     * the chunks will not be loaded during a scan
	     */

	    if (in_scan > 0) {
		new_serial = new_tags.serial_number;
		existing_serial = existing_tags.serial_number;
	    }

	    if ((in_scan > 0) &&
		(existing_cunk <= 0 ||
		 ((existing_serial + 1) & 3) == new_serial)) {
		/* Forward scanning.
		 * Use new
		 * Delete the old one and drop through to
		 * update the tnode
		 */
		yaffs_chunk_del(dev, existing_cunk, 1,
				__LINE__);
	    } else {
		/* Backward scanning or we want to use the
		 * existing one
		 * Delete the new one and return early so that
		 * the tnode isn't changed
		 */
		yaffs_chunk_del(dev, nand_chunk, 1, __LINE__);
		return YAFFS_OK;
	    }
	}

    }

    if (existing_cunk == 0)
	in->n_data_chunks++;

    yaffs_load_tnode_0(dev, tn, inode_chunk, nand_chunk);

    return YAFFS_OK;
}

static void yaffs_soft_del_chunk(struct yaffs_dev *dev, int chunk)
{
    struct yaffs_block_info *the_block;
    unsigned block_no;

    yaffs_trace(YAFFS_TRACE_DELETION, "soft delete chunk %d", chunk);

    block_no = chunk / dev->param.chunks_per_block;
    the_block = yaffs_get_block_info(dev, block_no);
    if (the_block) {
	the_block->soft_del_pages++;
	dev->n_free_chunks++;
	yaffs2_update_oldest_dirty_seq(dev, block_no, the_block);
    }
}

/* SoftDeleteWorker scans backwards through the tnode tree and soft deletes all
 * the chunks in the file.
 * All soft deleting does is increment the block's softdelete count and pulls
 * the chunk out of the tnode.
 * Thus, essentially this is the same as DeleteWorker except that the chunks
 * are soft deleted.
 */

static int yaffs_soft_del_worker(struct yaffs_obj *in, struct yaffs_tnode *tn,
				 u32 level, int chunk_offset)
{
    int i;
    int the_chunk;
    int all_done = 1;
    struct yaffs_dev *dev = in->my_dev;

    if (!tn)
	return 1;

    if (level > 0) {
	for (i = YAFFS_NTNODES_INTERNAL - 1;
	     all_done && i >= 0;
	     i--) {
	    if (tn->internal[i]) {
		all_done =
		    yaffs_soft_del_worker(in,
					  tn->internal[i],
					  level - 1,
					  (chunk_offset <<
					   YAFFS_TNODES_INTERNAL_BITS)
					  + i);
		if (all_done) {
		    yaffs_free_tnode(dev,
				     tn->internal[i]);
		    tn->internal[i] = NULL;
		} else {
		    /* Can this happen? */
		}
	    }
	}
	return (all_done) ? 1 : 0;
    }

    /* level 0 */
    for (i = YAFFS_NTNODES_LEVEL0 - 1; i >= 0; i--) {
	the_chunk = yaffs_get_group_base(dev, tn, i);
	if (the_chunk) {
	    yaffs_soft_del_chunk(dev, the_chunk);
	    yaffs_load_tnode_0(dev, tn, i, 0);
	}
    }
    return 1;
}

static void yaffs_remove_obj_from_dir(struct yaffs_obj *obj)
{
    struct yaffs_dev *dev = obj->my_dev;
    struct yaffs_obj *parent;

    yaffs_verify_obj_in_dir(obj);
    parent = obj->parent;

    yaffs_verify_dir(parent);

    if (dev && dev->param.remove_obj_fn)
	dev->param.remove_obj_fn(obj);

    list_del_init(&obj->siblings);
    obj->parent = NULL;

    yaffs_verify_dir(parent);
}

void yaffs_add_obj_to_dir(struct yaffs_obj *directory, struct yaffs_obj *obj)
{
    if (!directory) {
	yaffs_trace(YAFFS_TRACE_ALWAYS,
		    "tragedy: Trying to add an object to a null pointer directory"
		    );
	BUG();
	return;
    }
    if (directory->variant_type != YAFFS_OBJECT_TYPE_DIRECTORY) {
	yaffs_trace(YAFFS_TRACE_ALWAYS,
		    "tragedy: Trying to add an object to a non-directory"
		    );
	BUG();
    }

    if (obj->siblings.prev == NULL) {
	/* Not initialised */
	BUG();
    }

    yaffs_verify_dir(directory);

    yaffs_remove_obj_from_dir(obj);

    /* Now add it */
    list_add(&obj->siblings, &directory->variant.dir_variant.children);
    obj->parent = directory;

    if (directory == obj->my_dev->unlinked_dir
	|| directory == obj->my_dev->del_dir) {
	obj->unlinked = 1;
	obj->my_dev->n_unlinked_files++;
	obj->rename_allowed = 0;
    }

    yaffs_verify_dir(directory);
    yaffs_verify_obj_in_dir(obj);
}

static int yaffs_change_obj_name(struct yaffs_obj *obj,
				 struct yaffs_obj *new_dir,
				 const YCHAR *new_name, int force, int shadows)
{
    int unlink_op;
    int del_op;
    struct yaffs_obj *existing_target;

    if (new_dir == NULL)
	new_dir = obj->parent;	/* use the old directory */

    if (new_dir->variant_type != YAFFS_OBJECT_TYPE_DIRECTORY) {
	yaffs_trace(YAFFS_TRACE_ALWAYS,
		    "tragedy: yaffs_change_obj_name: new_dir is not a directory"
		    );
	BUG();
    }

    unlink_op = (new_dir == obj->my_dev->unlinked_dir);
    del_op = (new_dir == obj->my_dev->del_dir);

    existing_target = yaffs_find_by_name(new_dir, new_name);

    /* If the object is a file going into the unlinked directory,
     *   then it is OK to just stuff it in since duplicate names are OK.
     *   else only proceed if the new name does not exist and we're putting
     *   it into a directory.
     */
    if (!(unlink_op || del_op || force ||
	  shadows > 0 || !existing_target) ||
	new_dir->variant_type != YAFFS_OBJECT_TYPE_DIRECTORY)
	return YAFFS_FAIL;

    yaffs_set_obj_name(obj, new_name);
    obj->dirty = 1;
    yaffs_add_obj_to_dir(new_dir, obj);

    if (unlink_op)
	obj->unlinked = 1;

    /* If it is a deletion then we mark it as a shrink for gc  */
    if (yaffs_update_oh(obj, new_name, 0, del_op, shadows, NULL) >= 0)
	return YAFFS_OK;

    return YAFFS_FAIL;
}

/*------------------------ Short Operations Cache ------------------------------
 *   In many situations where there is no high level buffering  a lot of
 *   reads might be short sequential reads, and a lot of writes may be short
 *   sequential writes. eg. scanning/writing a jpeg file.
 *   In these cases, a short read/write cache can provide a huge perfomance
 *   benefit with dumb-as-a-rock code.
 *   In Linux, the page cache provides read buffering and the short op cache
 *   provides write buffering.
 *
 *   There are a small number (~10) of cache chunks per device so that we don't
 *   need a very intelligent search.
 */

static int yaffs_obj_cache_dirty(struct yaffs_obj *obj)
{
    struct yaffs_dev *dev = obj->my_dev;
    int i;
    struct yaffs_cache *cache;
    int n_caches = obj->my_dev->param.n_caches;

    for (i = 0; i < n_caches; i++) {
	cache = &dev->cache[i];
	if (cache->object == obj && cache->dirty)
	    return 1;
    }

    return 0;
}

static void yaffs_flush_file_cache(struct yaffs_obj *obj)
{
    struct yaffs_dev *dev = obj->my_dev;
    int lowest = -99;	/* Stop compiler whining. */
    int i;
    struct yaffs_cache *cache;
    int chunk_written = 0;
    int n_caches = obj->my_dev->param.n_caches;

    if (n_caches < 1)
	return;
    do {
	cache = NULL;

	/* Find the lowest dirty chunk for this object */
	for (i = 0; i < n_caches; i++) {
	    if (dev->cache[i].object == obj &&
		dev->cache[i].dirty) {
		if (!cache ||
		    dev->cache[i].chunk_id < lowest) {
		    cache = &dev->cache[i];
		    lowest = cache->chunk_id;
		}
	    }
	}

	if (cache && !cache->locked) {
	    /* Write it out and free it up */
	    chunk_written =
		yaffs_wr_data_obj(cache->object,
				  cache->chunk_id,
				  cache->data,
				  cache->n_bytes, 1);
	    cache->dirty = 0;
	    cache->object = NULL;
	}
    } while (cache && chunk_written > 0);

    if (cache)
	/* Hoosterman, disk full while writing cache out. */
	yaffs_trace(YAFFS_TRACE_ERROR,
		    "yaffs tragedy: no space during cache write");
}

/*yaffs_flush_whole_cache(dev)
 *
 *
 */

void yaffs_flush_whole_cache(struct yaffs_dev *dev)
{
    struct yaffs_obj *obj;
    int n_caches = dev->param.n_caches;
    int i;

    /* Find a dirty object in the cache and flush it...
     * until there are no further dirty objects.
     */
    do {
	obj = NULL;
	for (i = 0; i < n_caches && !obj; i++) {
	    if (dev->cache[i].object && dev->cache[i].dirty)
		obj = dev->cache[i].object;
	}
	if (obj)
	    yaffs_flush_file_cache(obj);
    } while (obj);

}

/* Grab us a cache chunk for use.
 * First look for an empty one.
 * Then look for the least recently used non-dirty one.
 * Then look for the least recently used dirty one...., flush and look again.
 */
static struct yaffs_cache *yaffs_grab_chunk_worker(struct yaffs_dev *dev)
{
    int i;

    if (dev->param.n_caches > 0) {
	for (i = 0; i < dev->param.n_caches; i++) {
	    if (!dev->cache[i].object)
		return &dev->cache[i];
	}
    }
    return NULL;
}

static struct yaffs_cache *yaffs_grab_chunk_cache(struct yaffs_dev *dev)
{
    struct yaffs_cache *cache;
    struct yaffs_obj *the_obj;
    int usage;
    int i;
    int pushout;

    if (dev->param.n_caches < 1)
	return NULL;

    /* Try find a non-dirty one... */

    cache = yaffs_grab_chunk_worker(dev);

    if (!cache) {
	/* They were all dirty, find the LRU object and flush
	 * its cache, then  find again.
	 * NB what's here is not very accurate,
	 * we actually flush the object with the LRU chunk.
	 */

	/* With locking we can't assume we can use entry zero,
	 * Set the_obj to a valid pointer for Coverity. */
	the_obj = dev->cache[0].object;
	usage = -1;
	cache = NULL;
	pushout = -1;

	for (i = 0; i < dev->param.n_caches; i++) {
	    if (dev->cache[i].object &&
		!dev->cache[i].locked &&
		(dev->cache[i].last_use < usage ||
		 !cache)) {
		usage = dev->cache[i].last_use;
		the_obj = dev->cache[i].object;
		cache = &dev->cache[i];
		pushout = i;
	    }
	}

	if (!cache || cache->dirty) {
	    /* Flush and try again */
	    yaffs_flush_file_cache(the_obj);
	    cache = yaffs_grab_chunk_worker(dev);
	}
    }
    return cache;
}

/* Find a cached chunk */
static struct yaffs_cache *yaffs_find_chunk_cache(const struct yaffs_obj *obj,
						  int chunk_id)
{
    struct yaffs_dev *dev = obj->my_dev;
    int i;

    if (dev->param.n_caches < 1)
	return NULL;

    for (i = 0; i < dev->param.n_caches; i++) {
	if (dev->cache[i].object == obj &&
	    dev->cache[i].chunk_id == chunk_id) {
	    dev->cache_hits++;

	    return &dev->cache[i];
	}
    }
    return NULL;
}

/* Mark the chunk for the least recently used algorithym */
static void yaffs_use_cache(struct yaffs_dev *dev, struct yaffs_cache *cache,
			    int is_write)
{
    int i;

    if (dev->param.n_caches < 1)
	return;

    if (dev->cache_last_use < 0 ||
	dev->cache_last_use > 100000000) {
	/* Reset the cache usages */
	for (i = 1; i < dev->param.n_caches; i++)
	    dev->cache[i].last_use = 0;

	dev->cache_last_use = 0;
    }
    dev->cache_last_use++;
    cache->last_use = dev->cache_last_use;

    if (is_write)
	cache->dirty = 1;
}

/* Invalidate a single cache page.
 * Do this when a whole page gets written,
 * ie the short cache for this page is no longer valid.
 */
static void yaffs_invalidate_chunk_cache(struct yaffs_obj *object, int chunk_id)
{
    struct yaffs_cache *cache;

    if (object->my_dev->param.n_caches > 0) {
	cache = yaffs_find_chunk_cache(object, chunk_id);

	if (cache)
	    cache->object = NULL;
    }
}

/* Invalidate all the cache pages associated with this object
 * Do this whenever ther file is deleted or resized.
 */
static void yaffs_invalidate_whole_cache(struct yaffs_obj *in)
{
    int i;
    struct yaffs_dev *dev = in->my_dev;

    if (dev->param.n_caches > 0) {
	/* Invalidate it. */
	for (i = 0; i < dev->param.n_caches; i++) {
	    if (dev->cache[i].object == in)
		dev->cache[i].object = NULL;
	}
    }
}

static void yaffs_unhash_obj(struct yaffs_obj *obj)
{
    int bucket;
    struct yaffs_dev *dev = obj->my_dev;

    /* If it is still linked into the bucket list, free from the list */
    if (!list_empty(&obj->hash_link)) {
	list_del_init(&obj->hash_link);
	bucket = yaffs_hash_fn(obj->obj_id);
	dev->obj_bucket[bucket].count--;
    }
}

/*  FreeObject frees up a Object and puts it back on the free list */
static void yaffs_free_obj(struct yaffs_obj *obj)
{
    struct yaffs_dev *dev;

    if (!obj) {
	BUG();
	return;
    }
    dev = obj->my_dev;
    yaffs_trace(YAFFS_TRACE_OS, "FreeObject %p inode %p",
		obj, obj->my_inode);
    if (obj->parent)
	BUG();
    if (!list_empty(&obj->siblings))
	BUG();

    if (obj->my_inode) {
	/* We're still hooked up to a cached inode.
	 * Don't delete now, but mark for later deletion
	 */
	obj->defered_free = 1;
	return;
    }

    yaffs_unhash_obj(obj);

    yaffs_free_raw_obj(dev, obj);
    dev->n_obj--;
    dev->checkpoint_blocks_required = 0;	/* force recalculation */
}

void yaffs_handle_defered_free(struct yaffs_obj *obj)
{
    if (obj->defered_free)
	yaffs_free_obj(obj);
}

static int yaffs_generic_obj_del(struct yaffs_obj *in)
{
    /* Iinvalidate the file's data in the cache, without flushing. */
    yaffs_invalidate_whole_cache(in);

    if (in->my_dev->param.is_yaffs2 && in->parent != in->my_dev->del_dir) {
	/* Move to unlinked directory so we have a deletion record */
	yaffs_change_obj_name(in, in->my_dev->del_dir, _Y("deleted"), 0,
			      0);
    }

    yaffs_remove_obj_from_dir(in);
    yaffs_chunk_del(in->my_dev, in->hdr_chunk, 1, __LINE__);
    in->hdr_chunk = 0;

    yaffs_free_obj(in);
    return YAFFS_OK;

}

static void yaffs_soft_del_file(struct yaffs_obj *obj)
{
    if (!obj->deleted ||
	obj->variant_type != YAFFS_OBJECT_TYPE_FILE ||
	obj->soft_del)
	return;

    if (obj->n_data_chunks <= 0) {
	/* Empty file with no duplicate object headers,
	 * just delete it immediately */
	yaffs_free_tnode(obj->my_dev, obj->variant.file_variant.top);
	obj->variant.file_variant.top = NULL;
	yaffs_trace(YAFFS_TRACE_TRACING,
		    "yaffs: Deleting empty file %d",
		    obj->obj_id);
	yaffs_generic_obj_del(obj);
    } else {
	yaffs_soft_del_worker(obj,
			      obj->variant.file_variant.top,
			      obj->variant.
			      file_variant.top_level, 0);
	obj->soft_del = 1;
    }
}

/* Pruning removes any part of the file structure tree that is beyond the
 * bounds of the file (ie that does not point to chunks).
 *
 * A file should only get pruned when its size is reduced.
 *
 * Before pruning, the chunks must be pulled from the tree and the
 * level 0 tnode entries must be zeroed out.
 * Could also use this for file deletion, but that's probably better handled
 * by a special case.
 *
 * This function is recursive. For levels > 0 the function is called again on
 * any sub-tree. For level == 0 we just check if the sub-tree has data.
 * If there is no data in a subtree then it is pruned.
 */

static struct yaffs_tnode *yaffs_prune_worker(struct yaffs_dev *dev,
					      struct yaffs_tnode *tn, u32 level,
					      int del0)
{
    int i;
    int has_data;

    if (!tn)
	return tn;

    has_data = 0;

    if (level > 0) {
	for (i = 0; i < YAFFS_NTNODES_INTERNAL; i++) {
	    if (tn->internal[i]) {
		tn->internal[i] =
		    yaffs_prune_worker(dev,
				       tn->internal[i],
				       level - 1,
				       (i == 0) ? del0 : 1);
	    }

	    if (tn->internal[i])
		has_data++;
	}
    } else {
	int tnode_size_u32 = dev->tnode_size / sizeof(u32);
	u32 *map = (u32 *) tn;

	for (i = 0; !has_data && i < tnode_size_u32; i++) {
	    if (map[i])
		has_data++;
	}
    }

    if (has_data == 0 && del0) {
	/* Free and return NULL */
	yaffs_free_tnode(dev, tn);
	tn = NULL;
    }
    return tn;
}

static int yaffs_prune_tree(struct yaffs_dev *dev,
			    struct yaffs_file_var *file_struct)
{
    int i;
    int has_data;
    int done = 0;
    struct yaffs_tnode *tn;

    if (file_struct->top_level < 1)
	return YAFFS_OK;

    file_struct->top =
	yaffs_prune_worker(dev, file_struct->top, file_struct->top_level, 0);

    /* Now we have a tree with all the non-zero branches NULL but
     * the height is the same as it was.
     * Let's see if we can trim internal tnodes to shorten the tree.
     * We can do this if only the 0th element in the tnode is in use
     * (ie all the non-zero are NULL)
     */

    while (file_struct->top_level && !done) {
	tn = file_struct->top;

	has_data = 0;
	for (i = 1; i < YAFFS_NTNODES_INTERNAL; i++) {
	    if (tn->internal[i])
		has_data++;
	}

	if (!has_data) {
	    file_struct->top = tn->internal[0];
	    file_struct->top_level--;
	    yaffs_free_tnode(dev, tn);
	} else {
	    done = 1;
	}
    }

    return YAFFS_OK;
}

/*-------------------- End of File Structure functions.-------------------*/

/* alloc_empty_obj gets us a clean Object.*/
static struct yaffs_obj *yaffs_alloc_empty_obj(struct yaffs_dev *dev)
{
    struct yaffs_obj *obj = yaffs_alloc_raw_obj(dev);

    if (!obj)
	return obj;

    dev->n_obj++;

    /* Now sweeten it up... */

    memset(obj, 0, sizeof(struct yaffs_obj));
    obj->being_created = 1;

    obj->my_dev = dev;
    obj->hdr_chunk = 0;
    obj->variant_type = YAFFS_OBJECT_TYPE_UNKNOWN;
    INIT_LIST_HEAD(&(obj->hard_links));
    INIT_LIST_HEAD(&(obj->hash_link));
    INIT_LIST_HEAD(&obj->siblings);

    /* Now make the directory sane */
    if (dev->root_dir) {
	obj->parent = dev->root_dir;
	list_add(&(obj->siblings),
		 &dev->root_dir->variant.dir_variant.children);
    }

    /* Add it to the lost and found directory.
     * NB Can't put root or lost-n-found in lost-n-found so
     * check if lost-n-found exists first
     */
    if (dev->lost_n_found)
	yaffs_add_obj_to_dir(dev->lost_n_found, obj);

    obj->being_created = 0;

    dev->checkpoint_blocks_required = 0;	/* force recalculation */

    return obj;
}

static int yaffs_find_nice_bucket(struct yaffs_dev *dev)
{
    int i;
    int l = 999;
    int lowest = 999999;

    /* Search for the shortest list or one that
     * isn't too long.
     */

    for (i = 0; i < 10 && lowest > 4; i++) {
	dev->bucket_finder++;
	dev->bucket_finder %= YAFFS_NOBJECT_BUCKETS;
	if (dev->obj_bucket[dev->bucket_finder].count < lowest) {
	    lowest = dev->obj_bucket[dev->bucket_finder].count;
	    l = dev->bucket_finder;
	}
    }

    return l;
}

static int yaffs_new_obj_id(struct yaffs_dev *dev)
{
    int bucket = yaffs_find_nice_bucket(dev);
    int found = 0;
    struct list_head *i;
    u32 n = (u32) bucket;

    /* Now find an object value that has not already been taken
     * by scanning the list.
     */

    while (!found) {
	found = 1;
	n += YAFFS_NOBJECT_BUCKETS;
	if (1 || dev->obj_bucket[bucket].count > 0) {
	    list_for_each(i, &dev->obj_bucket[bucket].list) {
		/* If there is already one in the list */
		if (i && list_entry(i, struct yaffs_obj,
				    hash_link)->obj_id == n) {
		    found = 0;
		}
	    }
	}
    }
    return n;
}

int defy_new_obj_id(struct yaffs_dev *dev) {
    return yaffs_new_obj_id(dev);
}


static void yaffs_hash_obj(struct yaffs_obj *in)
{
    int bucket = yaffs_hash_fn(in->obj_id);
    struct yaffs_dev *dev = in->my_dev;

    list_add(&in->hash_link, &dev->obj_bucket[bucket].list);
    dev->obj_bucket[bucket].count++;
}

struct yaffs_obj *yaffs_find_by_number(struct yaffs_dev *dev, u32 number)
{
    int bucket = yaffs_hash_fn(number);
    struct list_head *i;
    struct yaffs_obj *in;

    list_for_each(i, &dev->obj_bucket[bucket].list) {
	/* Look if it is in the list */
	in = list_entry(i, struct yaffs_obj, hash_link);
	if (in->obj_id == number) {
	    /* Don't show if it is defered free */
	    if (in->defered_free)
		return NULL;
	    return in;
	}
    }

    return NULL;
}

struct yaffs_obj *yaffs_new_obj(struct yaffs_dev *dev, int number,
				enum yaffs_obj_type type)
{
    struct yaffs_obj *the_obj = NULL;
    struct yaffs_tnode *tn = NULL;

    defy_printk("yaffs_new_obj", BEGIN_F);
    if (number < 0)
	number = yaffs_new_obj_id(dev);

    if (type == YAFFS_OBJECT_TYPE_FILE) {
	tn = yaffs_get_tnode(dev);
	if (!tn)
	    return NULL;
    }

    the_obj = yaffs_alloc_empty_obj(dev);
    if (!the_obj) {
	if (tn)
	    yaffs_free_tnode(dev, tn);
	return NULL;
    }

    the_obj->fake = 0;
    the_obj->rename_allowed = 1;
    the_obj->unlink_allowed = 1;
    the_obj->obj_id = number;
    yaffs_hash_obj(the_obj);
    the_obj->variant_type = type;
    yaffs_load_current_time(the_obj, 1, 1);

    switch (type) {
    case YAFFS_OBJECT_TYPE_FILE:
	the_obj->variant.file_variant.file_size = 0;
	the_obj->variant.file_variant.scanned_size = 0;
	the_obj->variant.file_variant.shrink_size = ~0; /* max */
	the_obj->variant.file_variant.top_level = 0;
	the_obj->variant.file_variant.top = tn;
	break;
    case YAFFS_OBJECT_TYPE_DIRECTORY:
	INIT_LIST_HEAD(&the_obj->variant.dir_variant.children);
	INIT_LIST_HEAD(&the_obj->variant.dir_variant.dirty);
	break;
    case YAFFS_OBJECT_TYPE_SYMLINK:
    case YAFFS_OBJECT_TYPE_HARDLINK:
    case YAFFS_OBJECT_TYPE_SPECIAL:
	/* No action required */
	break;
    case YAFFS_OBJECT_TYPE_UNKNOWN:
	/* todo this should not happen */
	break;
    }

    defy_printk("yaffs_new_obj", END_F);

    return the_obj;
}

static struct yaffs_obj *yaffs_create_fake_dir(struct yaffs_dev *dev,
					       int number, u32 mode)
{
    struct yaffs_obj *obj =
	yaffs_new_obj(dev, number, YAFFS_OBJECT_TYPE_DIRECTORY);
    
    if (!obj)
	return NULL;

    obj->fake = 1;	/* it is fake so it might not use NAND */
    obj->rename_allowed = 0;
    obj->unlink_allowed = 0;
    obj->deleted = 0;
    obj->unlinked = 0;
    obj->yst_mode = mode;
    obj->my_dev = dev;
    obj->hdr_chunk = 0;	/* Not a valid chunk. */
    return obj;

}


static void yaffs_init_tnodes_and_objs(struct yaffs_dev *dev)
{
    int i;

    dev->n_obj = 0;
    dev->n_tnodes = 0;
    yaffs_init_raw_tnodes_and_objs(dev);

    for (i = 0; i < YAFFS_NOBJECT_BUCKETS; i++) {
	INIT_LIST_HEAD(&dev->obj_bucket[i].list);
	dev->obj_bucket[i].count = 0;
    }
}

struct yaffs_obj *yaffs_find_or_create_by_number(struct yaffs_dev *dev,
						 int number,
						 enum yaffs_obj_type type)
{
    struct yaffs_obj *the_obj = NULL;

    defy_printk("yaffs_find_or_create_by_number", BEGIN_F);
    if (number > 0)
	the_obj = yaffs_find_by_number(dev, number);

    if (!the_obj)
	the_obj = yaffs_new_obj(dev, number, type);

    defy_printk("yaffs_find_or_create_by_number", END_F);

    return the_obj;

}

YCHAR *yaffs_clone_str(const YCHAR *str)
{
    YCHAR *new_str = NULL;
    int len;

    if (!str)
	str = _Y("");

    len = strnlen(str, YAFFS_MAX_ALIAS_LENGTH);
    new_str = kmalloc((len + 1) * sizeof(YCHAR), GFP_NOFS);
    if (new_str) {
	strncpy(new_str, str, len);
	new_str[len] = 0;
    }
    return new_str;

}
/*
 *yaffs_update_parent() handles fixing a directories mtime and ctime when a new
 * link (ie. name) is created or deleted in the directory.
 *
 * ie.
 *   create dir/a : update dir's mtime/ctime
 *   rm dir/a:   update dir's mtime/ctime
 *   modify dir/a: don't update dir's mtimme/ctime
 *
 * This can be handled immediately or defered. Defering helps reduce the number
 * of updates when many files in a directory are changed within a brief period.
 *
 * If the directory updating is defered then yaffs_update_dirty_dirs must be
 * called periodically.
 */

static void yaffs_update_parent(struct yaffs_obj *obj)
{
    struct yaffs_dev *dev;

    if (!obj)
	return;
    dev = obj->my_dev;
    obj->dirty = 1;
    yaffs_load_current_time(obj, 0, 1);
    if (dev->param.defered_dir_update) {
	struct list_head *link = &obj->variant.dir_variant.dirty;

	if (list_empty(link)) {
	    list_add(link, &dev->dirty_dirs);
	    yaffs_trace(YAFFS_TRACE_BACKGROUND,
			"Added object %d to dirty directories",
			obj->obj_id);
	}

    } else {
	yaffs_update_oh(obj, NULL, 0, 0, 0, NULL);
    }
}

void yaffs_update_dirty_dirs(struct yaffs_dev *dev)
{
    struct list_head *link;
    struct yaffs_obj *obj;
    struct yaffs_dir_var *d_s;
    union yaffs_obj_var *o_v;

    yaffs_trace(YAFFS_TRACE_BACKGROUND, "Update dirty directories");

    while (!list_empty(&dev->dirty_dirs)) {
	link = dev->dirty_dirs.next;
	list_del_init(link);

	d_s = list_entry(link, struct yaffs_dir_var, dirty);
	o_v = list_entry(d_s, union yaffs_obj_var, dir_variant);
	obj = list_entry(o_v, struct yaffs_obj, variant);

	yaffs_trace(YAFFS_TRACE_BACKGROUND, "Update directory %d",
		    obj->obj_id);

	if (obj->dirty)
	    yaffs_update_oh(obj, NULL, 0, 0, 0, NULL);
    }
}

/*
 * Mknod (create) a new object.
 * equiv_obj only has meaning for a hard link;
 * alias_str only has meaning for a symlink.
 * rdev only has meaning for devices (a subset of special objects)
 */

static struct yaffs_obj *yaffs_create_obj(enum yaffs_obj_type type,
					  struct yaffs_obj *parent,
					  const YCHAR *name,
					  u32 mode,
					  u32 uid,
					  u32 gid,
					  struct yaffs_obj *equiv_obj,
					  const YCHAR *alias_str, u32 rdev)
{
    struct yaffs_obj *in;
    YCHAR *str = NULL;
    struct yaffs_dev *dev = parent->my_dev;

    defy_printk("yaffs_create_obj", BEGIN_F);
    /* Check if the entry exists.
     * If it does then fail the call since we don't want a dup. */
    if (yaffs_find_by_name(parent, name))
	return NULL;

    if (type == YAFFS_OBJECT_TYPE_SYMLINK) {
	str = yaffs_clone_str(alias_str);
	if (!str)
	    return NULL;
    }

    in = yaffs_new_obj(dev, -1, type);

    if (!in) {
	kfree(str);
	return NULL;
    }

    // DEFY: This only gets called when creating an object other than a
    //         new level
    in->defy_level = parent->defy_level;

    defy_printk_indent();
    printk("level: %d\n", in->defy_level);

    in->hdr_chunk = 0;
    in->valid = 1;
    in->variant_type = type;

    in->yst_mode = mode;

    yaffs_attribs_init(in, gid, uid, rdev);

    in->n_data_chunks = 0;

    yaffs_set_obj_name(in, name);
    in->dirty = 1;

    yaffs_add_obj_to_dir(parent, in);

    in->my_dev = parent->my_dev;

    switch (type) {
    case YAFFS_OBJECT_TYPE_SYMLINK:
	in->variant.symlink_variant.alias = str;
	break;
    case YAFFS_OBJECT_TYPE_HARDLINK:
	in->variant.hardlink_variant.equiv_obj = equiv_obj;
	in->variant.hardlink_variant.equiv_id = equiv_obj->obj_id;
	list_add(&in->hard_links, &equiv_obj->hard_links);
	break;
    case YAFFS_OBJECT_TYPE_FILE:
    case YAFFS_OBJECT_TYPE_DIRECTORY:
    case YAFFS_OBJECT_TYPE_SPECIAL:
    case YAFFS_OBJECT_TYPE_UNKNOWN:
	/* do nothing */
	break;
    }

    if (yaffs_update_oh(in, name, 0, 0, 0, NULL) < 0) {
	/* Could not create the object header, fail */
	yaffs_del_obj(in);
	in = NULL;
    }

    if (in)
	yaffs_update_parent(parent);

    defy_printk("yaffs_create_obj", END_F);

    return in;
}

struct yaffs_obj *yaffs_create_file(struct yaffs_obj *parent,
				    const YCHAR *name, u32 mode, u32 uid,
				    u32 gid)
{
    return yaffs_create_obj(YAFFS_OBJECT_TYPE_FILE, parent, name, mode,
			    uid, gid, NULL, NULL, 0);
}

struct yaffs_obj *yaffs_create_dir(struct yaffs_obj *parent, const YCHAR *name,
				   u32 mode, u32 uid, u32 gid)
{
    return yaffs_create_obj(YAFFS_OBJECT_TYPE_DIRECTORY, parent, name,
			    mode, uid, gid, NULL, NULL, 0);
}

struct yaffs_obj *yaffs_create_special(struct yaffs_obj *parent,
				       const YCHAR *name, u32 mode, u32 uid,
				       u32 gid, u32 rdev)
{
    return yaffs_create_obj(YAFFS_OBJECT_TYPE_SPECIAL, parent, name, mode,
			    uid, gid, NULL, NULL, rdev);
}

struct yaffs_obj *yaffs_create_symlink(struct yaffs_obj *parent,
				       const YCHAR *name, u32 mode, u32 uid,
				       u32 gid, const YCHAR *alias)
{
    return yaffs_create_obj(YAFFS_OBJECT_TYPE_SYMLINK, parent, name, mode,
			    uid, gid, NULL, alias, 0);
}

/* yaffs_link_obj returns the object id of the equivalent object.*/
struct yaffs_obj *yaffs_link_obj(struct yaffs_obj *parent, const YCHAR * name,
				 struct yaffs_obj *equiv_obj)
{
    /* Get the real object in case we were fed a hard link obj */
    equiv_obj = yaffs_get_equivalent_obj(equiv_obj);

    if (yaffs_create_obj(YAFFS_OBJECT_TYPE_HARDLINK,
			 parent, name, 0, 0, 0,
			 equiv_obj, NULL, 0))
	return equiv_obj;

    return NULL;

}



/*---------------------- Block Management and Page Allocation -------------*/

static void yaffs_deinit_blocks(struct yaffs_dev *dev)
{
    if (dev->block_info_alt && dev->block_info)
	vfree(dev->block_info);
    else
	kfree(dev->block_info);

    dev->block_info_alt = 0;

    dev->block_info = NULL;

    if (dev->chunk_bits_alt && dev->chunk_bits)
	vfree(dev->chunk_bits);
    else
	kfree(dev->chunk_bits);
    dev->chunk_bits_alt = 0;
    dev->chunk_bits = NULL;
}

static int yaffs_init_blocks(struct yaffs_dev *dev)
{
    int n_blocks = dev->internal_end_block - dev->internal_start_block + 1;

    defy_printk("yaffs_init_blocks", BEGIN_F);

    dev->block_info = NULL;
    dev->chunk_bits = NULL;
    dev->alloc_block = -1;	/* force it to get a new one */

    /* If the first allocation strategy fails, thry the alternate one */
    dev->block_info =
	kmalloc(n_blocks * sizeof(struct yaffs_block_info), GFP_NOFS);
    if (!dev->block_info) {
	dev->block_info =
	    vmalloc(n_blocks * sizeof(struct yaffs_block_info));
	dev->block_info_alt = 1;
    } else {
	dev->block_info_alt = 0;
    }

    if (!dev->block_info)
	goto alloc_error;

    /* Set up dynamic blockinfo stuff. Round up bytes. */
    dev->chunk_bit_stride = (dev->param.chunks_per_block + 7) / 8;
    dev->chunk_bits =
	kmalloc(dev->chunk_bit_stride * n_blocks, GFP_NOFS);
    if (!dev->chunk_bits) {
	dev->chunk_bits =
	    vmalloc(dev->chunk_bit_stride * n_blocks);
	dev->chunk_bits_alt = 1;
    } else {
	dev->chunk_bits_alt = 0;
    }
    if (!dev->chunk_bits)
	goto alloc_error;


    memset(dev->block_info, 0, n_blocks * sizeof(struct yaffs_block_info));
    memset(dev->chunk_bits, 0, dev->chunk_bit_stride * n_blocks);

    defy_printk("yaffs_init_blocks", END_F);

    return YAFFS_OK;

 alloc_error:
    yaffs_deinit_blocks(dev);
    return YAFFS_FAIL;
}


void yaffs_block_became_dirty(struct yaffs_dev *dev, int block_no)
{
    struct yaffs_block_info *bi = yaffs_get_block_info(dev, block_no);
    int erased_ok = 0;
    int i;

    /* If the block is still healthy erase it and mark as clean.
     * If the block has had a data failure, then retire it.
     */

    yaffs_trace(YAFFS_TRACE_GC | YAFFS_TRACE_ERASE,
		"yaffs_block_became_dirty block %d state %d %s",
		block_no, bi->block_state,
		(bi->needs_retiring) ? "needs retiring" : "");

    defy_remove_block_from_level(dev, bi->defy_level, block_no);

    defy_printk("ERROR! yaffs_block_became_dirty", IN_F);

    yaffs2_clear_oldest_dirty_seq(dev, bi);

    bi->block_state = YAFFS_BLOCK_STATE_DIRTY;

    /* If this is the block being garbage collected then stop gc'ing */
    if (block_no == dev->gc_block)
	dev->gc_block = 0;

    /* if this block is currently the best candidate for gc
     * then drop as a candidate */
    if (block_no == dev->gc_dirtiest) {
	dev->gc_dirtiest = 0;
	dev->gc_pages_in_use = 0;
    }

    if (!bi->needs_retiring) {
	yaffs2_checkpt_invalidate(dev);
	erased_ok = yaffs_erase_block(dev, block_no);
	if (!erased_ok) {
	    dev->n_erase_failures++;
	    yaffs_trace(YAFFS_TRACE_ERROR | YAFFS_TRACE_BAD_BLOCKS,
			"**>> Erasure failed %d", block_no);
	}
    }

    /* Verify erasure if needed */
    if (erased_ok &&
	((yaffs_trace_mask & YAFFS_TRACE_ERASE) ||
	 !yaffs_skip_verification(dev))) {
	for (i = 0; i < dev->param.chunks_per_block; i++) {
	    if (!yaffs_check_chunk_erased(dev,
					  block_no *
					  dev->param.chunks_per_block + i)) {
		yaffs_trace(YAFFS_TRACE_ERROR,
			    ">>Block %d erasure supposedly OK, but chunk %d not erased",
			    block_no, i);
	    }
	}
    }

    if (!erased_ok) {
	/* We lost a block of free space */
	dev->n_free_chunks -= dev->param.chunks_per_block;
	yaffs_retire_block(dev, block_no);
	yaffs_trace(YAFFS_TRACE_ERROR | YAFFS_TRACE_BAD_BLOCKS,
		    "**>> Block %d retired", block_no);
	return;
    }

    /* Clean it up... */
    bi->block_state = YAFFS_BLOCK_STATE_EMPTY;
    bi->seq_number = 0;
    bi->pages_in_use = 0;
    bi->soft_del_pages = 0;
    bi->has_shrink_hdr = 0;
    bi->skip_erased_check = 1;	/* Clean, so no need to check */
    bi->gc_prioritise = 0;
    bi->has_summary=0;

    yaffs_clear_chunk_bits(dev, block_no);

    yaffs_trace(YAFFS_TRACE_ERASE, "Erased block %d", block_no);
}

static inline int yaffs_gc_process_chunk(struct yaffs_dev *dev,
					 struct yaffs_block_info *bi,
					 int old_chunk, u8 *buffer)
{
    int new_chunk;
    int mark_flash = 1;
    struct yaffs_ext_tags tags;
    struct yaffs_obj *object;
    int matching_chunk;
    int ret_val = YAFFS_OK;

    printk("GC!\n");

    memset(&tags, 0, sizeof(tags));
    // DEFY: set tags level
    tags.defy_level = bi->defy_level;
    
    yaffs_rd_chunk_tags_nand(dev, old_chunk,
			     buffer, &tags);
    object = yaffs_find_by_number(dev, tags.obj_id);
    // DEFY: set object level
    object->defy_level = bi->defy_level;

    yaffs_trace(YAFFS_TRACE_GC_DETAIL,
		"Collecting chunk in block %d, %d %d %d ",
		dev->gc_chunk, tags.obj_id,
		tags.chunk_id, tags.n_bytes);

    if (object && !yaffs_skip_verification(dev)) {
	if (tags.chunk_id == 0)
	    matching_chunk =
		object->hdr_chunk;
	else if (object->soft_del)
	    /* Defeat the test */
	    matching_chunk = old_chunk;
	else
	    matching_chunk =
		yaffs_find_chunk_in_file
		(object, tags.chunk_id,
		 NULL);

	if (old_chunk != matching_chunk)
	    yaffs_trace(YAFFS_TRACE_ERROR,
			"gc: page in gc mismatch: %d %d %d %d",
			old_chunk,
			matching_chunk,
			tags.obj_id,
			tags.chunk_id);
    }

    if (!object) {
	yaffs_trace(YAFFS_TRACE_ERROR,
		    "page %d in gc has no object: %d %d %d ",
		    old_chunk,
		    tags.obj_id, tags.chunk_id,
		    tags.n_bytes);
    }

    if (object &&
	object->deleted &&
	object->soft_del && tags.chunk_id != 0) {
	/* Data chunk in a soft deleted file,
	 * throw it away.
	 * It's a soft deleted data chunk,
	 * No need to copy this, just forget
	 * about it and fix up the object.
	 */

	/* Free chunks already includes
	 * softdeleted chunks, how ever this
	 * chunk is going to soon be really
	 * deleted which will increment free
	 * chunks. We have to decrement free
	 * chunks so this works out properly.
	 */
	dev->n_free_chunks--;
	bi->soft_del_pages--;

	object->n_data_chunks--;
	if (object->n_data_chunks <= 0) {
	    /* remeber to clean up obj */
	    dev->gc_cleanup_list[dev->n_clean_ups] = tags.obj_id;
	    dev->n_clean_ups++;
	}
	mark_flash = 0;
    } else if (object) {
	/* It's either a data chunk in a live
	 * file or an ObjectHeader, so we're
	 * interested in it.
	 * NB Need to keep the ObjectHeaders of
	 * deleted files until the whole file
	 * has been deleted off
	 */
	tags.serial_number++;
	dev->n_gc_copies++;

	if (tags.chunk_id == 0) {
	    /* It is an object Id,
	     * We need to nuke the
	     * shrinkheader flags since its
	     * work is done.
	     * Also need to clean up
	     * shadowing.
	     */
	    struct yaffs_obj_hdr *oh;
	    oh = (struct yaffs_obj_hdr *) buffer;

	    oh->is_shrink = 0;
	    tags.extra_is_shrink = 0;
	    oh->shadows_obj = 0;
	    oh->inband_shadowed_obj_id = 0;
	    tags.extra_shadows = 0;

	    /* Update file size */
	    if (object->variant_type == YAFFS_OBJECT_TYPE_FILE) {
		oh->file_size =
		    object->variant.file_variant.file_size;
		tags.extra_length = oh->file_size;
	    }

	    yaffs_verify_oh(object, oh, &tags, 1);
	    new_chunk =
		//yaffs_write_new_chunk(dev, (u8 *) oh, &tags, 1);
		defy_cache_chunk(dev, (u8 *) oh, &tags);
	} else {
	    new_chunk =
		//yaffs_write_new_chunk(dev, buffer, &tags, 1);
		defy_cache_chunk(dev, buffer, &tags);
	}

	if (new_chunk < 0) {
	    ret_val = YAFFS_FAIL;
	} else {

	    /* Now fix up the Tnodes etc. */

	    if (tags.chunk_id == 0) {
		/* It's a header */
		object->hdr_chunk = new_chunk;
		object->serial = tags.serial_number;
	    } else {
		/* It's a data chunk */
		yaffs_put_chunk_in_file(object, tags.chunk_id,
					new_chunk, 0);
	    }
	}
    }
    if (ret_val == YAFFS_OK)
	yaffs_chunk_del(dev, old_chunk, mark_flash, __LINE__);
    return ret_val;
}

static int yaffs_gc_block(struct yaffs_dev *dev, int block, int whole_block)
{
    int old_chunk;
    int ret_val = YAFFS_OK;
    int i;
    int is_checkpt_block;
    int max_copies;
    int chunks_before = yaffs_get_erased_chunks(dev);
    int chunks_after;
    struct yaffs_block_info *bi = yaffs_get_block_info(dev, block);

    defy_printk("yaffs_gc_block", BEGIN_F);

    is_checkpt_block = (bi->block_state == YAFFS_BLOCK_STATE_CHECKPOINT);

    yaffs_trace(YAFFS_TRACE_TRACING,
		"Collecting block %d, in use %d, shrink %d, whole_block %d",
		block, bi->pages_in_use, bi->has_shrink_hdr,
		whole_block);

    /*yaffs_verify_free_chunks(dev); */

    if (bi->block_state == YAFFS_BLOCK_STATE_FULL)
	bi->block_state = YAFFS_BLOCK_STATE_COLLECTING;

    bi->has_shrink_hdr = 0;	/* clear the flag so that the block can erase */

    dev->gc_disable = 1;

    yaffs_summary_gc(dev, block);

    if (is_checkpt_block || !yaffs_still_some_chunks(dev, block)) {
	yaffs_trace(YAFFS_TRACE_TRACING,
		    "Collecting block %d that has no chunks in use",
		    block);
	yaffs_block_became_dirty(dev, block);
    } else {

	u8 *buffer = yaffs_get_temp_buffer(dev);

	yaffs_verify_blk(dev, bi, block);

	max_copies = (whole_block) ? dev->param.chunks_per_block : 5;
	old_chunk = block * dev->param.chunks_per_block + dev->gc_chunk;

	for (/* init already done */ ;
				     ret_val == YAFFS_OK &&
					 dev->gc_chunk < dev->param.chunks_per_block &&
					 (bi->block_state == YAFFS_BLOCK_STATE_COLLECTING) &&
					 max_copies > 0;
				     dev->gc_chunk++, old_chunk++) {
	    if (yaffs_check_chunk_bit(dev, block, dev->gc_chunk)) {
		/* Page is in use and might need to be copied */
		max_copies--;
		ret_val = yaffs_gc_process_chunk(dev, bi,
						 old_chunk, buffer);
	    }
	}
	yaffs_release_temp_buffer(dev, buffer);
    }

    yaffs_verify_collected_blk(dev, bi, block);

    if (bi->block_state == YAFFS_BLOCK_STATE_COLLECTING) {
	/*
	 * The gc did not complete. Set block state back to FULL
	 * because checkpointing does not restore gc.
	 */
	bi->block_state = YAFFS_BLOCK_STATE_FULL;
    } else {
	/* The gc completed. */
	/* Do any required cleanups */
	for (i = 0; i < dev->n_clean_ups; i++) {
	    /* Time to delete the file too */
	    struct yaffs_obj *object =
		yaffs_find_by_number(dev, dev->gc_cleanup_list[i]);
	    if (object) {
		yaffs_free_tnode(dev,
				 object->variant.file_variant.top);
		object->variant.file_variant.top = NULL;
		yaffs_trace(YAFFS_TRACE_GC,
			    "yaffs: About to finally delete object %d",
			    object->obj_id);
		yaffs_generic_obj_del(object);
		object->my_dev->n_deleted_files--;
	    }

	}
	chunks_after = yaffs_get_erased_chunks(dev);
	if (chunks_before >= chunks_after)
	    yaffs_trace(YAFFS_TRACE_GC,
			"gc did not increase free chunks before %d after %d",
			chunks_before, chunks_after);
	dev->gc_block = 0;
	dev->gc_chunk = 0;
	dev->n_clean_ups = 0;
    }

    dev->gc_disable = 0;

    defy_printk("yaffs_gc_block", END_F);

    return ret_val;
}

/*
 * find_gc_block() selects the dirtiest block (or close enough)
 * for garbage collection.
 */

static unsigned yaffs_find_gc_block(struct yaffs_dev *dev,
				    int aggressive, int background)
{
    int i;
    int iterations;
    unsigned selected = 0;
    int prioritised = 0;
    int prioritised_exist = 0;
    struct yaffs_block_info *bi;
    int threshold;

    /* First let's see if we need to grab a prioritised block */
    if (dev->has_pending_prioritised_gc && !aggressive) {
	dev->gc_dirtiest = 0;
	bi = dev->block_info;
	for (i = dev->internal_start_block;
	     i <= dev->internal_end_block && !selected; i++) {

	    if (bi->gc_prioritise) {
		prioritised_exist = 1;
		if (bi->block_state == YAFFS_BLOCK_STATE_FULL &&
		    yaffs_block_ok_for_gc(dev, bi)) {
		    selected = i;
		    prioritised = 1;
		}
	    }
	    bi++;
	}

	/*
	 * If there is a prioritised block and none was selected then
	 * this happened because there is at least one old dirty block
	 * gumming up the works. Let's gc the oldest dirty block.
	 */

	if (prioritised_exist &&
	    !selected && dev->oldest_dirty_block > 0)
	    selected = dev->oldest_dirty_block;

	if (!prioritised_exist)	/* None found, so we can clear this */
	    dev->has_pending_prioritised_gc = 0;
    }

    /* If we're doing aggressive GC then we are happy to take a less-dirty
     * block, and search harder.
     * else (leasurely gc), then we only bother to do this if the
     * block has only a few pages in use.
     */

    if (!selected) {
	int pages_used;
	int n_blocks =
	    dev->internal_end_block - dev->internal_start_block + 1;
	if (aggressive) {
	    threshold = dev->param.chunks_per_block;
	    iterations = n_blocks;
	} else {
	    int max_threshold;

	    if (background)
		max_threshold = dev->param.chunks_per_block / 2;
	    else
		max_threshold = dev->param.chunks_per_block / 8;

	    if (max_threshold < YAFFS_GC_PASSIVE_THRESHOLD)
		max_threshold = YAFFS_GC_PASSIVE_THRESHOLD;

	    threshold = background ? (dev->gc_not_done + 2) * 2 : 0;
	    if (threshold < YAFFS_GC_PASSIVE_THRESHOLD)
		threshold = YAFFS_GC_PASSIVE_THRESHOLD;
	    if (threshold > max_threshold)
		threshold = max_threshold;

	    iterations = n_blocks / 16 + 1;
	    if (iterations > 100)
		iterations = 100;
	}

	for (i = 0;
	     i < iterations &&
		 (dev->gc_dirtiest < 1 ||
		  dev->gc_pages_in_use > YAFFS_GC_GOOD_ENOUGH);
	     i++) {
	    dev->gc_block_finder++;
	    if (dev->gc_block_finder < dev->internal_start_block ||
		dev->gc_block_finder > dev->internal_end_block)
		dev->gc_block_finder =
		    dev->internal_start_block;

	    bi = yaffs_get_block_info(dev, dev->gc_block_finder);

	    pages_used = bi->pages_in_use - bi->soft_del_pages;

	    if (bi->block_state == YAFFS_BLOCK_STATE_FULL &&
		pages_used < dev->param.chunks_per_block &&
		(dev->gc_dirtiest < 1 ||
		 pages_used < dev->gc_pages_in_use) &&
		yaffs_block_ok_for_gc(dev, bi)) {
		dev->gc_dirtiest = dev->gc_block_finder;
		dev->gc_pages_in_use = pages_used;
	    }
	}

	if (dev->gc_dirtiest > 0 && dev->gc_pages_in_use <= threshold)
	    selected = dev->gc_dirtiest;
    }

    /*
     * If nothing has been selected for a while, try the oldest dirty
     * because that's gumming up the works.
     */

    if (!selected && dev->param.is_yaffs2 &&
	dev->gc_not_done >= (background ? 10 : 20)) {
	yaffs2_find_oldest_dirty_seq(dev);
	if (dev->oldest_dirty_block > 0) {
	    selected = dev->oldest_dirty_block;
	    dev->gc_dirtiest = selected;
	    dev->oldest_dirty_gc_count++;
	    bi = yaffs_get_block_info(dev, selected);
	    dev->gc_pages_in_use =
		bi->pages_in_use - bi->soft_del_pages;
	} else {
	    dev->gc_not_done = 0;
	}
    }

    if (selected) {
	yaffs_trace(YAFFS_TRACE_GC,
		    "GC Selected block %d with %d free, prioritised:%d",
		    selected,
		    dev->param.chunks_per_block - dev->gc_pages_in_use,
		    prioritised);

	dev->n_gc_blocks++;
	if (background)
	    dev->bg_gcs++;

	dev->gc_dirtiest = 0;
	dev->gc_pages_in_use = 0;
	dev->gc_not_done = 0;
	if (dev->refresh_skip > 0)
	    dev->refresh_skip--;
    } else {
	dev->gc_not_done++;
	yaffs_trace(YAFFS_TRACE_GC,
		    "GC none: finder %d skip %d threshold %d dirtiest %d using %d oldest %d%s",
		    dev->gc_block_finder, dev->gc_not_done, threshold,
		    dev->gc_dirtiest, dev->gc_pages_in_use,
		    dev->oldest_dirty_block, background ? " bg" : "");
    }

    return selected;
}

/* New garbage collector
 * If we're very low on erased blocks then we do aggressive garbage collection
 * otherwise we do "leasurely" garbage collection.
 * Aggressive gc looks further (whole array) and will accept less dirty blocks.
 * Passive gc only inspects smaller areas and only accepts more dirty blocks.
 *
 * The idea is to help clear out space in a more spread-out manner.
 * Dunno if it really does anything useful.
 */
static int yaffs_check_gc(struct yaffs_dev *dev, int background)
{
    int aggressive = 0;
    int gc_ok = YAFFS_OK;
    int max_tries = 0;
    int min_erased;
    int erased_chunks;
    int checkpt_block_adjust;

    // DEFY: No GC for now, blocks able to be erased will be marked elsewhere
    return YAFFS_OK;

    if (dev->param.gc_control && (dev->param.gc_control(dev) & 1) == 0)
	return YAFFS_OK;

    if (dev->gc_disable)
	/* Bail out so we don't get recursive gc */
	return YAFFS_OK;

    /* This loop should pass the first time.
     * Only loops here if the collection does not increase space.
     */

    do {
	max_tries++;

	checkpt_block_adjust = yaffs_calc_checkpt_blocks_required(dev);

	min_erased =
	    dev->param.n_reserved_blocks + checkpt_block_adjust + 1;
	erased_chunks =
	    dev->n_erased_blocks * dev->param.chunks_per_block;

	/* If we need a block soon then do aggressive gc. */
	if (dev->n_erased_blocks < min_erased)
	    aggressive = 1;
	else {
	    if (!background
		&& erased_chunks > (dev->n_free_chunks / 4))
		break;

	    if (dev->gc_skip > 20)
		dev->gc_skip = 20;
	    if (erased_chunks < dev->n_free_chunks / 2 ||
		dev->gc_skip < 1 || background)
		aggressive = 0;
	    else {
		dev->gc_skip--;
		break;
	    }
	}

	dev->gc_skip = 5;

	/* If we don't already have a block being gc'd then see if we
	 * should start another */

	if (dev->gc_block < 1 && !aggressive) {
	    dev->gc_block = yaffs2_find_refresh_block(dev);
	    dev->gc_chunk = 0;
	    dev->n_clean_ups = 0;
	}
	if (dev->gc_block < 1) {
	    dev->gc_block =
		yaffs_find_gc_block(dev, aggressive, background);
	    dev->gc_chunk = 0;
	    dev->n_clean_ups = 0;
	}

	if (dev->gc_block > 0) {
	    dev->all_gcs++;
	    if (!aggressive)
		dev->passive_gc_count++;

	    yaffs_trace(YAFFS_TRACE_GC,
			"yaffs: GC n_erased_blocks %d aggressive %d",
			dev->n_erased_blocks, aggressive);

	    gc_ok = yaffs_gc_block(dev, dev->gc_block, aggressive);
	}

	if (dev->n_erased_blocks < (dev->param.n_reserved_blocks) &&
	    dev->gc_block > 0) {
	    yaffs_trace(YAFFS_TRACE_GC,
			"yaffs: GC !!!no reclaim!!! n_erased_blocks %d after try %d block %d",
			dev->n_erased_blocks, max_tries,
			dev->gc_block);
	}
    } while ((dev->n_erased_blocks < dev->param.n_reserved_blocks) &&
	     (dev->gc_block > 0) && (max_tries < 2));

    return aggressive ? gc_ok : YAFFS_OK;
}

/*
 * yaffs_bg_gc()
 * Garbage collects. Intended to be called from a background thread.
 * Returns non-zero if at least half the free chunks are erased.
 */
int yaffs_bg_gc(struct yaffs_dev *dev, unsigned urgency)
{
    int erased_chunks = dev->n_erased_blocks * dev->param.chunks_per_block;

    yaffs_trace(YAFFS_TRACE_BACKGROUND, "Background gc %u", urgency);

    yaffs_check_gc(dev, 1);
    return erased_chunks > dev->n_free_chunks / 2;
}

/*-------------------- Data file manipulation -----------------*/

static int yaffs_rd_data_obj(struct yaffs_obj *in, int inode_chunk, u8 * buffer)
{
    // DEFY: tags were previously NULLs
    struct yaffs_ext_tags tags;
    int nand_chunk;

    memset(&tags, 0, sizeof(struct yaffs_ext_tags));
    tags.defy_level = in->defy_level;
    nand_chunk = yaffs_find_chunk_in_file(in, inode_chunk, NULL);

    if (nand_chunk >= 0)
	return yaffs_rd_chunk_tags_nand(in->my_dev, nand_chunk,
					buffer, &tags);
    else {
	yaffs_trace(YAFFS_TRACE_NANDACCESS,
		    "Chunk %d not found zero instead",
		    nand_chunk);
	/* get sane (zero) data if you read a hole */
	memset(buffer, 0, in->my_dev->data_bytes_per_chunk);
	return 0;
    }

}

void yaffs_chunk_del(struct yaffs_dev *dev, int chunk_id, int mark_flash,
		     int lyn)
{
    int block;
    int page;
    struct yaffs_ext_tags tags;
    struct yaffs_block_info *bi;

    if (chunk_id <= 0)
	return;

    defy_printk("yaffs_chunk_del", BEGIN_F);
    dev->n_deletions++;
    block = chunk_id / dev->param.chunks_per_block;
    page = chunk_id % dev->param.chunks_per_block;

    if (!yaffs_check_chunk_bit(dev, block, page))
	yaffs_trace(YAFFS_TRACE_VERIFY,
		    "Deleting invalid chunk %d", chunk_id);

    bi = yaffs_get_block_info(dev, block);

    yaffs2_update_oldest_dirty_seq(dev, block, bi);

    yaffs_trace(YAFFS_TRACE_DELETION,
		"line %d delete of chunk %d",
		lyn, chunk_id);

    if (!dev->param.is_yaffs2 && mark_flash &&
	bi->block_state != YAFFS_BLOCK_STATE_COLLECTING) {

	memset(&tags, 0, sizeof(tags));
	tags.is_deleted = 1;
	yaffs_wr_chunk_tags_nand(dev, chunk_id, NULL, &tags);
	yaffs_handle_chunk_update(dev, chunk_id, &tags);
    } else {
	dev->n_unmarked_deletions++;
    }

    /* Pull out of the management area.
     * If the whole block became dirty, this will kick off an erasure.
     */
    if (bi->block_state == YAFFS_BLOCK_STATE_ALLOCATING ||
	bi->block_state == YAFFS_BLOCK_STATE_FULL ||
	bi->block_state == YAFFS_BLOCK_STATE_NEEDS_SCAN ||
	bi->block_state == YAFFS_BLOCK_STATE_COLLECTING) {
	dev->n_free_chunks++;
	yaffs_clear_chunk_bit(dev, block, page);
	bi->pages_in_use--;

	if (bi->pages_in_use == 0 &&
	    !bi->has_shrink_hdr &&
	    bi->block_state != YAFFS_BLOCK_STATE_ALLOCATING &&
	    bi->block_state != YAFFS_BLOCK_STATE_NEEDS_SCAN) {
	    yaffs_block_became_dirty(dev, block);
	}
    }
    defy_printk("yaffs_chunk_del", END_F);
}

static int yaffs_wr_data_obj(struct yaffs_obj *in, int inode_chunk,
			     const u8 *buffer, int n_bytes, int use_reserve)
{
    /* Find old chunk Need to do this to get serial number
     * Write new one and patch into tree.
     * Invalidate old tags.
     */

    int prev_chunk_id;
    struct yaffs_ext_tags prev_tags;
    int new_chunk_id;
    struct yaffs_ext_tags new_tags;
    struct yaffs_dev *dev = in->my_dev;

    defy_printk("yaffs_wr_data_obj", BEGIN_F);
    // DEFY
    prev_tags.defy_level = in->defy_level;

    yaffs_check_gc(dev, 0);

    /* Get the previous chunk at this location in the file if it exists.
     * If it does not exist then put a zero into the tree. This creates
     * the tnode now, rather than later when it is harder to clean up.
     */

    prev_chunk_id = yaffs_find_chunk_in_file(in, inode_chunk, &prev_tags);
    if (prev_chunk_id < 1 &&
	!yaffs_put_chunk_in_file(in, inode_chunk, 0, 0))
	return 0;

    /* Set up new tags */
    memset(&new_tags, 0, sizeof(new_tags));

    new_tags.chunk_id = inode_chunk;
    new_tags.obj_id = in->obj_id;
    new_tags.serial_number =
	(prev_chunk_id > 0) ? prev_tags.serial_number + 1 : 1;
    new_tags.n_bytes = n_bytes;

    // DEFY: Set level in tags
    in->defy_level = in->parent->defy_level;
    new_tags.defy_level = in->defy_level;
    defy_printk_indent();
    printk("level: %d\n", in->defy_level);

    if (n_bytes < 1 || n_bytes > dev->param.total_bytes_per_chunk) {
	yaffs_trace(YAFFS_TRACE_ERROR,
		    "Writing %d bytes to chunk!!!!!!!!!",
		    n_bytes);
	BUG();
    }

    new_chunk_id =
	//yaffs_write_new_chunk(dev, buffer, &new_tags, use_reserve);
	defy_cache_chunk(dev, buffer, &new_tags);

    if (new_chunk_id > 0) {
	yaffs_put_chunk_in_file(in, inode_chunk, new_chunk_id, 0);

	if (prev_chunk_id > 0)
	    yaffs_chunk_del(dev, prev_chunk_id, 1, __LINE__);

	yaffs_verify_file_sane(in);
    }

    defy_printk("yaffs_wr_data_obj", END_F);

    return new_chunk_id;

}



static int yaffs_do_xattrib_mod(struct yaffs_obj *obj, int set,
				const YCHAR *name, const void *value, int size,
				int flags)
{
    struct yaffs_xattr_mod xmod;
    int result;

    xmod.set = set;
    xmod.name = name;
    xmod.data = value;
    xmod.size = size;
    xmod.flags = flags;
    xmod.result = -ENOSPC;

    result = yaffs_update_oh(obj, NULL, 0, 0, 0, &xmod);

    if (result > 0)
	return xmod.result;
    else
	return -ENOSPC;
}

static int yaffs_apply_xattrib_mod(struct yaffs_obj *obj, char *buffer,
				   struct yaffs_xattr_mod *xmod)
{
    int retval = 0;
    int x_offs = sizeof(struct yaffs_obj_hdr);
    struct yaffs_dev *dev = obj->my_dev;
    int x_size = dev->data_bytes_per_chunk - sizeof(struct yaffs_obj_hdr);
    char *x_buffer = buffer + x_offs;

    if (xmod->set)
	retval =
	    nval_set(x_buffer, x_size, xmod->name, xmod->data,
		     xmod->size, xmod->flags);
    else
	retval = nval_del(x_buffer, x_size, xmod->name);

    obj->has_xattr = nval_hasvalues(x_buffer, x_size);
    obj->xattr_known = 1;
    xmod->result = retval;

    return retval;
}

static int yaffs_do_xattrib_fetch(struct yaffs_obj *obj, const YCHAR *name,
				  void *value, int size)
{
    char *buffer = NULL;
    int result;
    struct yaffs_ext_tags tags;
    struct yaffs_dev *dev = obj->my_dev;
    int x_offs = sizeof(struct yaffs_obj_hdr);
    int x_size = dev->data_bytes_per_chunk - sizeof(struct yaffs_obj_hdr);
    char *x_buffer;
    int retval = 0;

    if (obj->hdr_chunk < 1)
	return -ENODATA;

    /* If we know that the object has no xattribs then don't do all the
     * reading and parsing.
     */
    if (obj->xattr_known && !obj->has_xattr) {
	if (name)
	    return -ENODATA;
	else
	    return 0;
    }

    buffer = (char *)yaffs_get_temp_buffer(dev);
    if (!buffer)
	return -ENOMEM;

    // DEFY: set tags level
    tags.defy_level = obj->defy_level;

    result =
	yaffs_rd_chunk_tags_nand(dev, obj->hdr_chunk, (u8 *) buffer, &tags);

    if (result != YAFFS_OK)
	retval = -ENOENT;
    else {
	x_buffer = buffer + x_offs;

	if (!obj->xattr_known) {
	    obj->has_xattr = nval_hasvalues(x_buffer, x_size);
	    obj->xattr_known = 1;
	}

	if (name)
	    retval = nval_get(x_buffer, x_size, name, value, size);
	else
	    retval = nval_list(x_buffer, x_size, value, size);
    }
    yaffs_release_temp_buffer(dev, (u8 *) buffer);
    return retval;
}

int yaffs_set_xattrib(struct yaffs_obj *obj, const YCHAR * name,
		      const void *value, int size, int flags)
{
    return yaffs_do_xattrib_mod(obj, 1, name, value, size, flags);
}

int yaffs_remove_xattrib(struct yaffs_obj *obj, const YCHAR * name)
{
    return yaffs_do_xattrib_mod(obj, 0, name, NULL, 0, 0);
}

int yaffs_get_xattrib(struct yaffs_obj *obj, const YCHAR * name, void *value,
		      int size)
{
    return yaffs_do_xattrib_fetch(obj, name, value, size);
}

int yaffs_list_xattrib(struct yaffs_obj *obj, char *buffer, int size)
{
    return yaffs_do_xattrib_fetch(obj, NULL, buffer, size);
}

static void yaffs_check_obj_details_loaded(struct yaffs_obj *in)
{
    u8 *buf;
    struct yaffs_obj_hdr *oh;
    struct yaffs_dev *dev;
    struct yaffs_ext_tags tags;
    int result;
    int alloc_failed = 0;

    if (!in || !in->lazy_loaded || in->hdr_chunk < 1)
	return;

    dev = in->my_dev;
    in->lazy_loaded = 0;
    buf = yaffs_get_temp_buffer(dev);

    // DEFY: set tags level
    tags.defy_level = in->defy_level;

    result = yaffs_rd_chunk_tags_nand(dev, in->hdr_chunk, buf, &tags);
    oh = (struct yaffs_obj_hdr *)buf;

    in->yst_mode = oh->yst_mode;
    yaffs_load_attribs(in, oh);
    yaffs_set_obj_name_from_oh(in, oh);

    if (in->variant_type == YAFFS_OBJECT_TYPE_SYMLINK) {
	in->variant.symlink_variant.alias =
	    yaffs_clone_str(oh->alias);
	if (!in->variant.symlink_variant.alias)
	    alloc_failed = 1;	/* Not returned */
    }
    yaffs_release_temp_buffer(dev, buf);
}

static void yaffs_load_name_from_oh(struct yaffs_dev *dev, YCHAR *name,
				    const YCHAR *oh_name, int buff_size)
{
#ifdef CONFIG_YAFFS_AUTO_UNICODE
    if (dev->param.auto_unicode) {
	if (*oh_name) {
	    /* It is an ASCII name, do an ASCII to
	     * unicode conversion */
	    const char *ascii_oh_name = (const char *)oh_name;
	    int n = buff_size - 1;
	    while (n > 0 && *ascii_oh_name) {
		*name = *ascii_oh_name;
		name++;
		ascii_oh_name++;
		n--;
	    }
	} else {
	    strncpy(name, oh_name + 1, buff_size - 1);
	}
    } else
#endif
	{	    
	    strncpy(name, oh_name, buff_size - 1);
	}
}
    
static void yaffs_load_oh_from_name(struct yaffs_dev *dev, YCHAR *oh_name,
				    const YCHAR *name)
{
#ifdef CONFIG_YAFFS_AUTO_UNICODE
    
    int is_ascii;
    YCHAR *w;

    if (dev->param.auto_unicode) {

	is_ascii = 1;
	w = name;

	/* Figure out if the name will fit in ascii character set */
	while (is_ascii && *w) {
	    if ((*w) & 0xff00)
		is_ascii = 0;
	    w++;
	}

	if (is_ascii) {
	    /* It is an ASCII name, so convert unicode to ascii */
	    char *ascii_oh_name = (char *)oh_name;
	    int n = YAFFS_MAX_NAME_LENGTH - 1;
	    while (n > 0 && *name) {
		*ascii_oh_name = *name;
		name++;
		ascii_oh_name++;
		n--;
	    }
	} else {
	    /* Unicode name, so save starting at the second YCHAR */
	    *oh_name = 0;
	    strncpy(oh_name + 1, name, YAFFS_MAX_NAME_LENGTH - 2);
	}
    } else
#endif
	{
	    strncpy(oh_name, name, YAFFS_MAX_NAME_LENGTH - 1);
	}
}

/* UpdateObjectHeader updates the header on NAND for an object.
 * If name is not NULL, then that new name is used.
 */
int yaffs_update_oh(struct yaffs_obj *in, const YCHAR *name, int force,
		    int is_shrink, int shadows, struct yaffs_xattr_mod *xmod)
{
    struct yaffs_block_info *bi;
    struct yaffs_dev *dev = in->my_dev;
    int prev_chunk_id;
    int ret_val = 0;
    int result = 0;
    int new_chunk_id;
    struct yaffs_ext_tags new_tags;
    struct yaffs_ext_tags old_tags;
    const YCHAR *alias = NULL;
    u8 *buffer = NULL;
    YCHAR old_name[YAFFS_MAX_NAME_LENGTH + 1];
    struct yaffs_obj_hdr *oh = NULL;

    /* DEFY: We don't want the root directory info EVER written to disk.
     *         It would give away what levels were open.  Besides, we want
     *         to create a new root directory at every mount.  So we should
     *         never checkpoint, but instead create a DEFY end-chunk to
     *         inform where to write next.  Unless we want to use checkpoint
     *         data to rebuild directory structures.
     */
    defy_printk("yaffs_update_oh", BEGIN_F);

    strcpy(old_name, _Y("silly old name"));

    if (in->fake && in != dev->root_dir && !force && !xmod)
	return ret_val;

    // DEFY: Do our own GC
    //yaffs_check_gc(dev, 0);
    yaffs_check_obj_details_loaded(in);

    buffer = yaffs_get_temp_buffer(in->my_dev);
    oh = (struct yaffs_obj_hdr *)buffer;

    prev_chunk_id = in->hdr_chunk;

    if (prev_chunk_id > 0) {
	defy_printk_indent();
	printk("oh level is %d\n", in->defy_level);
	// DEFY: set tags level
	old_tags.defy_level = in->defy_level;

	result = yaffs_rd_chunk_tags_nand(dev, prev_chunk_id,
					  buffer, &old_tags);

	yaffs_verify_oh(in, oh, &old_tags, 0);
	memcpy(old_name, oh->name, sizeof(oh->name));
	memset(buffer, 0xff, sizeof(struct yaffs_obj_hdr));
    } else {
	memset(buffer, 0xff, dev->data_bytes_per_chunk);
    }

    oh->type = in->variant_type;
    oh->yst_mode = in->yst_mode;
    oh->shadows_obj = oh->inband_shadowed_obj_id = shadows;

    yaffs_load_attribs_oh(oh, in);

    if (in->parent)
	oh->parent_obj_id = in->parent->obj_id;
    else
	oh->parent_obj_id = 0;

    if (name && *name) {
	memset(oh->name, 0, sizeof(oh->name));
	yaffs_load_oh_from_name(dev, oh->name, name);
    } else if (prev_chunk_id > 0) {
	memcpy(oh->name, old_name, sizeof(oh->name));
    } else {
	memset(oh->name, 0, sizeof(oh->name));
    }

    oh->is_shrink = is_shrink;

    // DEFY: Set the encryption level based on directory hierarchy
    // DEFY: If parent is root, the level has already been set properly
    if (in->parent && in->parent->defy_level != -1)
	in->defy_level = in->parent->defy_level;
    defy_printk_indent();
    printk("name : %s\n", oh->name);
    defy_printk_indent();
    printk("level: %d\n", in->defy_level);
    defy_printk_indent();
    printk("equiv_id: %d\n", oh->equiv_id);
    defy_printk_indent();
    printk("yst_mode: %d\n", oh->yst_mode);
    defy_printk_indent();
    printk("file_size: %d\n", oh->file_size);
    defy_printk_indent();
    printk("yst_uid: %d\n", oh->yst_uid);
    defy_printk_indent();
    printk("yst_gid: %d\n", oh->yst_gid);
    defy_printk_indent();
    printk("yst_atime: %d\n", oh->yst_atime);
    defy_printk_indent();
    printk("yst_mtime: %d\n", oh->yst_mtime);
    defy_printk_indent();
    printk("yst_ctime: %d\n", oh->yst_ctime);

    switch (in->variant_type) {
    case YAFFS_OBJECT_TYPE_UNKNOWN:
	/* Should not happen */
	break;
    case YAFFS_OBJECT_TYPE_FILE:
	oh->file_size =
	    (oh->parent_obj_id == YAFFS_OBJECTID_DELETED ||
	     oh->parent_obj_id == YAFFS_OBJECTID_UNLINKED) ?
	    0 : in->variant.file_variant.file_size;
	break;
    case YAFFS_OBJECT_TYPE_HARDLINK:
	oh->equiv_id = in->variant.hardlink_variant.equiv_id;
	break;
    case YAFFS_OBJECT_TYPE_SPECIAL:
	/* Do nothing */
	break;
    case YAFFS_OBJECT_TYPE_DIRECTORY:
	/* Do nothing */
	break;
    case YAFFS_OBJECT_TYPE_SYMLINK:
	alias = in->variant.symlink_variant.alias;
	if (!alias)
	    alias = _Y("no alias");
	strncpy(oh->alias, alias, YAFFS_MAX_ALIAS_LENGTH);
	oh->alias[YAFFS_MAX_ALIAS_LENGTH] = 0;
	break;
    }

    /* process any xattrib modifications */
    if (xmod)
	yaffs_apply_xattrib_mod(in, (char *)buffer, xmod);

    /* Tags */
    memset(&new_tags, 0, sizeof(new_tags));
    in->serial++;
    new_tags.chunk_id = 0;
    new_tags.obj_id = in->obj_id;
    new_tags.serial_number = in->serial;
    // DEFY: Ensure the chunk is encrypted at the level of this object
    new_tags.defy_level = in->defy_level;

    /* Add extra info for file header */
    new_tags.extra_available = 1;
    new_tags.extra_parent_id = oh->parent_obj_id;
    new_tags.extra_length = oh->file_size;
    new_tags.extra_is_shrink = oh->is_shrink;
    new_tags.extra_equiv_id = oh->equiv_id;
    new_tags.extra_shadows = (oh->shadows_obj > 0) ? 1 : 0;
    new_tags.extra_obj_type = in->variant_type;
    yaffs_verify_oh(in, oh, &new_tags, 1);

    /* Create new chunk in NAND */
    // DEFY: write it to disk if it isn't a top-level directory (e.g. root)
    if(in->defy_level != -1) { 
	new_chunk_id =
	    //yaffs_write_new_chunk(dev, buffer, &new_tags,
	    //			  (prev_chunk_id > 0) ? 1 : 0);
	    defy_cache_chunk(dev, buffer, &new_tags);
    } else {
	new_chunk_id = 0;
    }

    if (buffer)
	yaffs_release_temp_buffer(dev, buffer);

    if (new_chunk_id < 0) {
	defy_printk("Bad chunk ID", IN_F);
	defy_printk("yaffs_update_oh", END_F);
	return new_chunk_id;
    }

    in->hdr_chunk = new_chunk_id;

    if (prev_chunk_id > 0)
	yaffs_chunk_del(dev, prev_chunk_id, 1, __LINE__);

    if (!yaffs_obj_cache_dirty(in))
	in->dirty = 0;

    /* If this was a shrink, then mark the block
     * that the chunk lives on */
    if (is_shrink) {
	bi = yaffs_get_block_info(in->my_dev,
				  new_chunk_id /
				  in->my_dev->param.chunks_per_block);
	bi->has_shrink_hdr = 1;
    }

    defy_printk("yaffs_update_oh", END_F);

    return new_chunk_id;
}

/*--------------------- File read/write ------------------------
 * Read and write have very similar structures.
 * In general the read/write has three parts to it
 * An incomplete chunk to start with (if the read/write is not chunk-aligned)
 * Some complete chunks
 * An incomplete chunk to end off with
 *
 * Curve-balls: the first chunk might also be the last chunk.
 */

int yaffs_file_rd(struct yaffs_obj *in, u8 * buffer, loff_t offset, int n_bytes)
{
    int chunk;
    u32 start;
    int n_copy;
    int n = n_bytes;
    int n_done = 0;
    struct yaffs_cache *cache;
    struct yaffs_dev *dev;

    dev = in->my_dev;

    while (n > 0) {
	yaffs_addr_to_chunk(dev, offset, &chunk, &start);
	chunk++;

	/* OK now check for the curveball where the start and end are in
	 * the same chunk.
	 */
	if ((start + n) < dev->data_bytes_per_chunk)
	    n_copy = n;
	else
	    n_copy = dev->data_bytes_per_chunk - start;

	cache = yaffs_find_chunk_cache(in, chunk);

	/* If the chunk is already in the cache or it is less than
	 * a whole chunk or we're using inband tags then use the cache
	 * (if there is caching) else bypass the cache.
	 */
	if (cache || n_copy != dev->data_bytes_per_chunk ||
	    dev->param.inband_tags) {
	    if (dev->param.n_caches > 0) {

		/* If we can't find the data in the cache,
		 * then load it up. */

		if (!cache) {
		    cache =
			yaffs_grab_chunk_cache(in->my_dev);
		    cache->object = in;
		    cache->chunk_id = chunk;
		    cache->dirty = 0;
		    cache->locked = 0;
		    yaffs_rd_data_obj(in, chunk,
				      cache->data);
		    cache->n_bytes = 0;
		}

		yaffs_use_cache(dev, cache, 0);

		cache->locked = 1;

		memcpy(buffer, &cache->data[start], n_copy);

		cache->locked = 0;
	    } else {
		/* Read into the local buffer then copy.. */

		u8 *local_buffer =
		    yaffs_get_temp_buffer(dev);
		yaffs_rd_data_obj(in, chunk, local_buffer);

		memcpy(buffer, &local_buffer[start], n_copy);

		yaffs_release_temp_buffer(dev, local_buffer);
	    }
	} else {
	    /* A full chunk. Read directly into the buffer. */
	    yaffs_rd_data_obj(in, chunk, buffer);
	}
	n -= n_copy;
	offset += n_copy;
	buffer += n_copy;
	n_done += n_copy;
    }
    return n_done;
}

int yaffs_do_file_wr(struct yaffs_obj *in, const u8 *buffer, loff_t offset,
		     int n_bytes, int write_trhrough)
{

    int chunk;
    u32 start;
    int n_copy;
    int n = n_bytes;
    int n_done = 0;
    int n_writeback;
    int start_write = offset;
    int chunk_written = 0;
    u32 n_bytes_read;
    u32 chunk_start;
    struct yaffs_dev *dev;

    dev = in->my_dev;

    while (n > 0 && chunk_written >= 0) {
	yaffs_addr_to_chunk(dev, offset, &chunk, &start);

	if (chunk * dev->data_bytes_per_chunk + start != offset ||
	    start >= dev->data_bytes_per_chunk) {
	    yaffs_trace(YAFFS_TRACE_ERROR,
			"AddrToChunk of offset %d gives chunk %d start %d",
			(int)offset, chunk, start);
	}
	chunk++;	/* File pos to chunk in file offset */

	/* OK now check for the curveball where the start and end are in
	 * the same chunk.
	 */

	if ((start + n) < dev->data_bytes_per_chunk) {
	    n_copy = n;

	    /* Now calculate how many bytes to write back....
	     * If we're overwriting and not writing to then end of
	     * file then we need to write back as much as was there
	     * before.
	     */

	    chunk_start = ((chunk - 1) * dev->data_bytes_per_chunk);

	    if (chunk_start > in->variant.file_variant.file_size)
		n_bytes_read = 0;	/* Past end of file */
	    else
		n_bytes_read =
		    in->variant.file_variant.file_size -
		    chunk_start;

	    if (n_bytes_read > dev->data_bytes_per_chunk)
		n_bytes_read = dev->data_bytes_per_chunk;

	    n_writeback =
		(n_bytes_read >
		 (start + n)) ? n_bytes_read : (start + n);

	    if (n_writeback < 0 ||
		n_writeback > dev->data_bytes_per_chunk)
		BUG();

	} else {
	    n_copy = dev->data_bytes_per_chunk - start;
	    n_writeback = dev->data_bytes_per_chunk;
	}

	if (n_copy != dev->data_bytes_per_chunk ||
	    dev->param.inband_tags) {
	    /* An incomplete start or end chunk (or maybe both
	     * start and end chunk), or we're using inband tags,
	     * so we want to use the cache buffers.
	     */
	    if (dev->param.n_caches > 0) {
		struct yaffs_cache *cache;

		/* If we can't find the data in the cache, then
		 * load the cache */
		cache = yaffs_find_chunk_cache(in, chunk);

		if (!cache &&
		    yaffs_check_alloc_available(dev, 1)) {
		    cache = yaffs_grab_chunk_cache(dev);
		    cache->object = in;
		    cache->chunk_id = chunk;
		    cache->dirty = 0;
		    cache->locked = 0;
		    yaffs_rd_data_obj(in, chunk,
				      cache->data);
		} else if (cache &&
			   !cache->dirty &&
			   !yaffs_check_alloc_available(dev,
							1)) {
		    /* Drop the cache if it was a read cache
		     * item and no space check has been made
		     * for it.
		     */
		    cache = NULL;
		}

		if (cache) {
		    yaffs_use_cache(dev, cache, 1);
		    cache->locked = 1;

		    memcpy(&cache->data[start], buffer,
			   n_copy);

		    cache->locked = 0;
		    cache->n_bytes = n_writeback;

		    if (write_trhrough) {
			chunk_written =
			    yaffs_wr_data_obj
			    (cache->object,
			     cache->chunk_id,
			     cache->data,
			     cache->n_bytes, 1);
			cache->dirty = 0;
		    }
		} else {
		    chunk_written = -1;	/* fail write */
		}
	    } else {
		/* An incomplete start or end chunk (or maybe
		 * both start and end chunk). Read into the
		 * local buffer then copy over and write back.
		 */

		u8 *local_buffer = yaffs_get_temp_buffer(dev);

		yaffs_rd_data_obj(in, chunk, local_buffer);
		memcpy(&local_buffer[start], buffer, n_copy);

		chunk_written =
		    yaffs_wr_data_obj(in, chunk,
				      local_buffer,
				      n_writeback, 0);

		yaffs_release_temp_buffer(dev, local_buffer);
	    }
	} else {
	    /* A full chunk. Write directly from the buffer. */

	    chunk_written =
		yaffs_wr_data_obj(in, chunk, buffer,
				  dev->data_bytes_per_chunk, 0);

	    /* Since we've overwritten the cached data,
	     * we better invalidate it. */
	    yaffs_invalidate_chunk_cache(in, chunk);
	}

	if (chunk_written >= 0) {
	    n -= n_copy;
	    offset += n_copy;
	    buffer += n_copy;
	    n_done += n_copy;
	}
    }

    /* Update file object */

    if ((start_write + n_done) > in->variant.file_variant.file_size)
	in->variant.file_variant.file_size = (start_write + n_done);

    in->dirty = 1;
    return n_done;
}

int yaffs_wr_file(struct yaffs_obj *in, const u8 *buffer, loff_t offset,
		  int n_bytes, int write_trhrough)
{
    yaffs2_handle_hole(in, offset);
    return yaffs_do_file_wr(in, buffer, offset, n_bytes, write_trhrough);
}

/* ---------------------- File resizing stuff ------------------ */

static void yaffs_prune_chunks(struct yaffs_obj *in, int new_size)
{

    struct yaffs_dev *dev = in->my_dev;
    int old_size = in->variant.file_variant.file_size;
    int i;
    int chunk_id;
    int last_del = 1 + (old_size - 1) / dev->data_bytes_per_chunk;
    int start_del = 1 + (new_size + dev->data_bytes_per_chunk - 1) /
	dev->data_bytes_per_chunk;


    /* Delete backwards so that we don't end up with holes if
     * power is lost part-way through the operation.
     */
    for (i = last_del; i >= start_del; i--) {
	/* NB this could be optimised somewhat,
	 * eg. could retrieve the tags and write them without
	 * using yaffs_chunk_del
	 */

	chunk_id = yaffs_find_del_file_chunk(in, i, NULL);

	if (chunk_id < 1)
	    continue;

	if (chunk_id <
	    (dev->internal_start_block * dev->param.chunks_per_block) ||
	    chunk_id >=
	    ((dev->internal_end_block + 1) *
	     dev->param.chunks_per_block)) {
	    yaffs_trace(YAFFS_TRACE_ALWAYS,
			"Found daft chunk_id %d for %d",
			chunk_id, i);
	} else {
	    in->n_data_chunks--;
	    yaffs_chunk_del(dev, chunk_id, 1, __LINE__);
	}
    }
}

void yaffs_resize_file_down(struct yaffs_obj *obj, loff_t new_size)
{
    int new_full;
    u32 new_partial;
    struct yaffs_dev *dev = obj->my_dev;

    yaffs_addr_to_chunk(dev, new_size, &new_full, &new_partial);

    yaffs_prune_chunks(obj, new_size);

    if (new_partial != 0) {
	int last_chunk = 1 + new_full;
	u8 *local_buffer = yaffs_get_temp_buffer(dev);

	/* Rewrite the last chunk with its new size and zero pad */
	yaffs_rd_data_obj(obj, last_chunk, local_buffer);
	memset(local_buffer + new_partial, 0,
	       dev->data_bytes_per_chunk - new_partial);

	yaffs_wr_data_obj(obj, last_chunk, local_buffer,
			  new_partial, 1);

	yaffs_release_temp_buffer(dev, local_buffer);
    }

    obj->variant.file_variant.file_size = new_size;

    yaffs_prune_tree(dev, &obj->variant.file_variant);
}

int yaffs_resize_file(struct yaffs_obj *in, loff_t new_size)
{
    struct yaffs_dev *dev = in->my_dev;
    int old_size = in->variant.file_variant.file_size;

    yaffs_flush_file_cache(in);
    yaffs_invalidate_whole_cache(in);

    yaffs_check_gc(dev, 0);

    if (in->variant_type != YAFFS_OBJECT_TYPE_FILE)
	return YAFFS_FAIL;

    if (new_size == old_size)
	return YAFFS_OK;

    if (new_size > old_size) {
	yaffs2_handle_hole(in, new_size);
	in->variant.file_variant.file_size = new_size;
    } else {
	/* new_size < old_size */
	yaffs_resize_file_down(in, new_size);
    }

    /* Write a new object header to reflect the resize.
     * show we've shrunk the file, if need be
     * Do this only if the file is not in the deleted directories
     * and is not shadowed.
     */
    if (in->parent &&
	!in->is_shadowed &&
	in->parent->obj_id != YAFFS_OBJECTID_UNLINKED &&
	in->parent->obj_id != YAFFS_OBJECTID_DELETED)
	yaffs_update_oh(in, NULL, 0, 0, 0, NULL);

    return YAFFS_OK;
}

int yaffs_flush_file(struct yaffs_obj *in, int update_time, int data_sync)
{
    if (!in->dirty)
	return YAFFS_OK;

    yaffs_flush_file_cache(in);

    if (data_sync)
	return YAFFS_OK;

    if (update_time)
	yaffs_load_current_time(in, 0, 0);

    return (yaffs_update_oh(in, NULL, 0, 0, 0, NULL) >= 0) ?
	YAFFS_OK : YAFFS_FAIL;
}


/* yaffs_del_file deletes the whole file data
 * and the inode associated with the file.
 * It does not delete the links associated with the file.
 */
static int yaffs_unlink_file_if_needed(struct yaffs_obj *in)
{
    int ret_val;
    int del_now = 0;
    struct yaffs_dev *dev = in->my_dev;

    if (!in->my_inode)
	del_now = 1;

    if (del_now) {
	ret_val =
	    yaffs_change_obj_name(in, in->my_dev->del_dir,
				  _Y("deleted"), 0, 0);
	yaffs_trace(YAFFS_TRACE_TRACING,
		    "yaffs: immediate deletion of file %d",
		    in->obj_id);
	in->deleted = 1;
	in->my_dev->n_deleted_files++;
	if (dev->param.disable_soft_del || dev->param.is_yaffs2)
	    yaffs_resize_file(in, 0);
	yaffs_soft_del_file(in);
    } else {
	ret_val =
	    yaffs_change_obj_name(in, in->my_dev->unlinked_dir,
				  _Y("unlinked"), 0, 0);
    }
    return ret_val;
}

int yaffs_del_file(struct yaffs_obj *in)
{
    int ret_val = YAFFS_OK;
    int deleted;	/* Need to cache value on stack if in is freed */
    struct yaffs_dev *dev = in->my_dev;

    if (dev->param.disable_soft_del || dev->param.is_yaffs2)
	yaffs_resize_file(in, 0);

    if (in->n_data_chunks > 0) {
	/* Use soft deletion if there is data in the file.
	 * That won't be the case if it has been resized to zero.
	 */
	if (!in->unlinked)
	    ret_val = yaffs_unlink_file_if_needed(in);

	deleted = in->deleted;

	if (ret_val == YAFFS_OK && in->unlinked && !in->deleted) {
	    in->deleted = 1;
	    deleted = 1;
	    in->my_dev->n_deleted_files++;
	    yaffs_soft_del_file(in);
	}
	return deleted ? YAFFS_OK : YAFFS_FAIL;
    } else {
	/* The file has no data chunks so we toss it immediately */
	yaffs_free_tnode(in->my_dev, in->variant.file_variant.top);
	in->variant.file_variant.top = NULL;
	yaffs_generic_obj_del(in);

	return YAFFS_OK;
    }
}

int yaffs_is_non_empty_dir(struct yaffs_obj *obj)
{
    return (obj &&
	    obj->variant_type == YAFFS_OBJECT_TYPE_DIRECTORY) &&
	!(list_empty(&obj->variant.dir_variant.children));
}

static int yaffs_del_dir(struct yaffs_obj *obj)
{
    /* First check that the directory is empty. */
    if (yaffs_is_non_empty_dir(obj))
	return YAFFS_FAIL;

    return yaffs_generic_obj_del(obj);
}

static int yaffs_del_symlink(struct yaffs_obj *in)
{
    kfree(in->variant.symlink_variant.alias);
    in->variant.symlink_variant.alias = NULL;

    return yaffs_generic_obj_del(in);
}

static int yaffs_del_link(struct yaffs_obj *in)
{
    /* remove this hardlink from the list associated with the equivalent
     * object
     */
    list_del_init(&in->hard_links);
    return yaffs_generic_obj_del(in);
}

int yaffs_del_obj(struct yaffs_obj *obj)
{
    int ret_val = -1;

    switch (obj->variant_type) {
    case YAFFS_OBJECT_TYPE_FILE:
	ret_val = yaffs_del_file(obj);
	break;
    case YAFFS_OBJECT_TYPE_DIRECTORY:
	if (!list_empty(&obj->variant.dir_variant.dirty)) {
	    yaffs_trace(YAFFS_TRACE_BACKGROUND,
			"Remove object %d from dirty directories",
			obj->obj_id);
	    list_del_init(&obj->variant.dir_variant.dirty);
	}
	return yaffs_del_dir(obj);
	break;
    case YAFFS_OBJECT_TYPE_SYMLINK:
	ret_val = yaffs_del_symlink(obj);
	break;
    case YAFFS_OBJECT_TYPE_HARDLINK:
	ret_val = yaffs_del_link(obj);
	break;
    case YAFFS_OBJECT_TYPE_SPECIAL:
	ret_val = yaffs_generic_obj_del(obj);
	break;
    case YAFFS_OBJECT_TYPE_UNKNOWN:
	ret_val = 0;
	break;		/* should not happen. */
    }
    return ret_val;
}

static int yaffs_unlink_worker(struct yaffs_obj *obj)
{
    int del_now = 0;

    if (!obj)
	return YAFFS_FAIL;

    if (!obj->my_inode)
	del_now = 1;

    yaffs_update_parent(obj->parent);

    if (obj->variant_type == YAFFS_OBJECT_TYPE_HARDLINK) {
	return yaffs_del_link(obj);
    } else if (!list_empty(&obj->hard_links)) {
	/* Curve ball: We're unlinking an object that has a hardlink.
	 *
	 * This problem arises because we are not strictly following
	 * The Linux link/inode model.
	 *
	 * We can't really delete the object.
	 * Instead, we do the following:
	 * - Select a hardlink.
	 * - Unhook it from the hard links
	 * - Move it from its parent directory so that the rename works.
	 * - Rename the object to the hardlink's name.
	 * - Delete the hardlink
	 */

	struct yaffs_obj *hl;
	struct yaffs_obj *parent;
	int ret_val;
	YCHAR name[YAFFS_MAX_NAME_LENGTH + 1];

	hl = list_entry(obj->hard_links.next, struct yaffs_obj,
			hard_links);

	yaffs_get_obj_name(hl, name, YAFFS_MAX_NAME_LENGTH + 1);
	parent = hl->parent;

	list_del_init(&hl->hard_links);

	yaffs_add_obj_to_dir(obj->my_dev->unlinked_dir, hl);

	ret_val = yaffs_change_obj_name(obj, parent, name, 0, 0);

	if (ret_val == YAFFS_OK)
	    ret_val = yaffs_generic_obj_del(hl);

	return ret_val;

    } else if (del_now) {
	switch (obj->variant_type) {
	case YAFFS_OBJECT_TYPE_FILE:
	    return yaffs_del_file(obj);
	    break;
	case YAFFS_OBJECT_TYPE_DIRECTORY:
	    list_del_init(&obj->variant.dir_variant.dirty);
	    return yaffs_del_dir(obj);
	    break;
	case YAFFS_OBJECT_TYPE_SYMLINK:
	    return yaffs_del_symlink(obj);
	    break;
	case YAFFS_OBJECT_TYPE_SPECIAL:
	    return yaffs_generic_obj_del(obj);
	    break;
	case YAFFS_OBJECT_TYPE_HARDLINK:
	case YAFFS_OBJECT_TYPE_UNKNOWN:
	default:
	    return YAFFS_FAIL;
	}
    } else if (yaffs_is_non_empty_dir(obj)) {
	return YAFFS_FAIL;
    } else {
	return yaffs_change_obj_name(obj, obj->my_dev->unlinked_dir,
				     _Y("unlinked"), 0, 0);
    }
}

static int yaffs_unlink_obj(struct yaffs_obj *obj)
{
    if (obj && obj->unlink_allowed)
	return yaffs_unlink_worker(obj);

    return YAFFS_FAIL;
}

int yaffs_unlinker(struct yaffs_obj *dir, const YCHAR *name)
{
    struct yaffs_obj *obj;

    obj = yaffs_find_by_name(dir, name);
    return yaffs_unlink_obj(obj);
}

/* Note:
 * If old_name is NULL then we take old_dir as the object to be renamed.
 */
int yaffs_rename_obj(struct yaffs_obj *old_dir, const YCHAR *old_name,
		     struct yaffs_obj *new_dir, const YCHAR *new_name)
{
    struct yaffs_obj *obj = NULL;
    struct yaffs_obj *existing_target = NULL;
    int force = 0;
    int result;
    struct yaffs_dev *dev;

    if (!old_dir || old_dir->variant_type != YAFFS_OBJECT_TYPE_DIRECTORY) {
	BUG();
	return YAFFS_FAIL;
    }
    if (!new_dir || new_dir->variant_type != YAFFS_OBJECT_TYPE_DIRECTORY) {
	BUG();
	return YAFFS_FAIL;
    }

    dev = old_dir->my_dev;

#ifdef CONFIG_YAFFS_CASE_INSENSITIVE
    /* Special case for case insemsitive systems.
     * While look-up is case insensitive, the name isn't.
     * Therefore we might want to change x.txt to X.txt
     */
    if (old_dir == new_dir &&
	old_name && new_name &&
	strcmp(old_name, new_name) == 0)
	force = 1;
#endif

    if (strnlen(new_name, YAFFS_MAX_NAME_LENGTH + 1) >
	YAFFS_MAX_NAME_LENGTH)
	/* ENAMETOOLONG */
	return YAFFS_FAIL;

    if (old_name)
	obj = yaffs_find_by_name(old_dir, old_name);
    else{
	obj = old_dir;
	old_dir = obj->parent;
    }

    if (obj && obj->rename_allowed) {
	/* Now handle an existing target, if there is one */
	existing_target = yaffs_find_by_name(new_dir, new_name);
	if (yaffs_is_non_empty_dir(existing_target)) {
	    return YAFFS_FAIL;	/* ENOTEMPTY */
	} else if (existing_target && existing_target != obj) {
	    /* Nuke the target first, using shadowing,
	     * but only if it isn't the same object.
	     *
	     * Note we must disable gc here otherwise it can mess
	     * up the shadowing.
	     *
	     */
	    dev->gc_disable = 1;
	    yaffs_change_obj_name(obj, new_dir, new_name, force,
				  existing_target->obj_id);
	    existing_target->is_shadowed = 1;
	    yaffs_unlink_obj(existing_target);
	    dev->gc_disable = 0;
	}

	result = yaffs_change_obj_name(obj, new_dir, new_name, 1, 0);

	yaffs_update_parent(old_dir);
	if (new_dir != old_dir)
	    yaffs_update_parent(new_dir);

	return result;
    }
    return YAFFS_FAIL;
}

/*----------------------- Initialisation Scanning ---------------------- */

void yaffs_handle_shadowed_obj(struct yaffs_dev *dev, int obj_id,
			       int backward_scanning)
{
    struct yaffs_obj *obj;

    if (backward_scanning) {
	/* Handle YAFFS2 case (backward scanning)
	 * If the shadowed object exists then ignore.
	 */
	obj = yaffs_find_by_number(dev, obj_id);
	if (obj)
	    return;
    }

    /* Let's create it (if it does not exist) assuming it is a file so that
     * it can do shrinking etc.
     * We put it in unlinked dir to be cleaned up after the scanning
     */
    obj =
	yaffs_find_or_create_by_number(dev, obj_id, YAFFS_OBJECT_TYPE_FILE);
    if (!obj)
	return;
    obj->is_shadowed = 1;
    yaffs_add_obj_to_dir(dev->unlinked_dir, obj);
    obj->variant.file_variant.shrink_size = 0;
    obj->valid = 1;		/* So that we don't read any other info. */
}

void yaffs_link_fixup(struct yaffs_dev *dev, struct list_head *hard_list)
{
    struct list_head *lh;
    struct list_head *save;
    struct yaffs_obj *hl;
    struct yaffs_obj *in;
    int count = 0;

    list_for_each_safe(lh, save, hard_list) {
	count++;
	hl = list_entry(lh, struct yaffs_obj, hard_links);
	in = yaffs_find_by_number(dev,
				  hl->variant.hardlink_variant.equiv_id);

	if (in) {
	    /* Add the hardlink pointers */
	    hl->variant.hardlink_variant.equiv_obj = in;
	    list_add(&hl->hard_links, &in->hard_links);
	} else {
	    /* Todo Need to report/handle this better.
	     * Got a problem... hardlink to a non-existant object
	     */
	    hl->variant.hardlink_variant.equiv_obj = NULL;
	    INIT_LIST_HEAD(&hl->hard_links);
	}
    }
    defy_printk_indent();
    printk("There were %d hard links\n", count);
}

static void yaffs_strip_deleted_objs(struct yaffs_dev *dev)
{
    /*
     *  Sort out state of unlinked and deleted objects after scanning.
     */
    struct list_head *i;
    struct list_head *n;
    struct yaffs_obj *l;

    if (dev->read_only)
	return;

    /* Soft delete all the unlinked files */
    list_for_each_safe(i, n,
		       &dev->unlinked_dir->variant.dir_variant.children) {
	l = list_entry(i, struct yaffs_obj, siblings);
	yaffs_del_obj(l);
    }

    list_for_each_safe(i, n, &dev->del_dir->variant.dir_variant.children) {
	l = list_entry(i, struct yaffs_obj, siblings);
	yaffs_del_obj(l);
    }
}

/*
 * This code iterates through all the objects making sure that they are rooted.
 * Any unrooted objects are re-rooted in lost+found.
 * An object needs to be in one of:
 * - Directly under deleted, unlinked
 * - Directly or indirectly under root.
 *
 * Note:
 *  This code assumes that we don't ever change the current relationships
 *  between directories:
 *   root_dir->parent == unlinked_dir->parent == del_dir->parent == NULL
 *   lost-n-found->parent == root_dir
 *
 * This fixes the problem where directories might have inadvertently been
 * deleted leaving the object "hanging" without being rooted in the
 * directory tree.
 */

static int yaffs_has_null_parent(struct yaffs_dev *dev, struct yaffs_obj *obj)
{
    return (obj == dev->del_dir ||
	    obj == dev->unlinked_dir || obj == dev->root_dir);
}

static void yaffs_fix_hanging_objs(struct yaffs_dev *dev)
{
    struct yaffs_obj *obj;
    struct yaffs_obj *parent;
    int i;
    struct list_head *lh;
    struct list_head *n;
    int depth_limit;
    int hanging;

    if (dev->read_only)
	return;

    /* Iterate through the objects in each hash entry,
     * looking at each object.
     * Make sure it is rooted.
     */

    for (i = 0; i < YAFFS_NOBJECT_BUCKETS; i++) {
	list_for_each_safe(lh, n, &dev->obj_bucket[i].list) {
	    obj = list_entry(lh, struct yaffs_obj, hash_link);
	    parent = obj->parent;

	    if (yaffs_has_null_parent(dev, obj)) {
		/* These directories are not hanging */
		hanging = 0;
	    } else if (!parent ||
		       parent->variant_type !=
		       YAFFS_OBJECT_TYPE_DIRECTORY) {
		hanging = 1;
	    } else if (yaffs_has_null_parent(dev, parent)) {
		hanging = 0;
	    } else {
		/*
		 * Need to follow the parent chain to
		 * see if it is hanging.
		 */
		hanging = 0;
		depth_limit = 100;

		while (parent != dev->root_dir &&
		       parent->parent &&
		       parent->parent->variant_type ==
		       YAFFS_OBJECT_TYPE_DIRECTORY &&
		       depth_limit > 0) {
		    parent = parent->parent;
		    depth_limit--;
		}
		if (parent != dev->root_dir)
		    hanging = 1;
	    }
	    if (hanging) {
		yaffs_trace(YAFFS_TRACE_SCAN,
			    "Hanging object %d moved to lost and found",
			    obj->obj_id);
		yaffs_add_obj_to_dir(dev->lost_n_found, obj);
	    }
	}
    }
}

/*
 * Delete directory contents for cleaning up lost and found.
 */
static void yaffs_del_dir_contents(struct yaffs_obj *dir)
{
    struct yaffs_obj *obj;
    struct list_head *lh;
    struct list_head *n;

    if (dir->variant_type != YAFFS_OBJECT_TYPE_DIRECTORY)
	BUG();

    list_for_each_safe(lh, n, &dir->variant.dir_variant.children) {
	obj = list_entry(lh, struct yaffs_obj, siblings);
	if (obj->variant_type == YAFFS_OBJECT_TYPE_DIRECTORY)
	    yaffs_del_dir_contents(obj);
	yaffs_trace(YAFFS_TRACE_SCAN,
		    "Deleting lost_found object %d",
		    obj->obj_id);
	yaffs_unlink_obj(obj);
    }
}

static void yaffs_empty_l_n_f(struct yaffs_dev *dev)
{
    yaffs_del_dir_contents(dev->lost_n_found);
}


struct yaffs_obj *yaffs_find_by_name(struct yaffs_obj *directory,
				     const YCHAR *name)
{
    int sum;
    struct list_head *i;
    YCHAR buffer[YAFFS_MAX_NAME_LENGTH + 1];
    struct yaffs_obj *l;

    if (!name)
	return NULL;

    if (!directory) {
	yaffs_trace(YAFFS_TRACE_ALWAYS,
		    "tragedy: yaffs_find_by_name: null pointer directory"
		    );
	BUG();
	return NULL;
    }
    if (directory->variant_type != YAFFS_OBJECT_TYPE_DIRECTORY) {
	yaffs_trace(YAFFS_TRACE_ALWAYS,
		    "tragedy: yaffs_find_by_name: non-directory"
		    );
	BUG();
    }

    sum = yaffs_calc_name_sum(name);

    list_for_each(i, &directory->variant.dir_variant.children) {
	l = list_entry(i, struct yaffs_obj, siblings);

	if (l->parent != directory)
	    BUG();

	yaffs_check_obj_details_loaded(l);

	/* Special case for lost-n-found */
	if (l->obj_id == YAFFS_OBJECTID_LOSTNFOUND) {
	    if (!strcmp(name, YAFFS_LOSTNFOUND_NAME))
		return l;
	} else if (l->sum == sum || l->hdr_chunk <= 0) {
	    /* LostnFound chunk called Objxxx
	     * Do a real check
	     */
	    yaffs_get_obj_name(l, buffer,
			       YAFFS_MAX_NAME_LENGTH + 1);
	    if (strncmp(name, buffer, YAFFS_MAX_NAME_LENGTH) == 0)
		return l;
	}
    }
    return NULL;
}

/* GetEquivalentObject dereferences any hard links to get to the
 * actual object.
 */

struct yaffs_obj *yaffs_get_equivalent_obj(struct yaffs_obj *obj)
{
    if (obj && obj->variant_type == YAFFS_OBJECT_TYPE_HARDLINK) {
	obj = obj->variant.hardlink_variant.equiv_obj;
	yaffs_check_obj_details_loaded(obj);
    }
    return obj;
}

/*
 *  A note or two on object names.
 *  * If the object name is missing, we then make one up in the form objnnn
 *
 *  * ASCII names are stored in the object header's name field from byte zero
 *  * Unicode names are historically stored starting from byte zero.
 *
 * Then there are automatic Unicode names...
 * The purpose of these is to save names in a way that can be read as
 * ASCII or Unicode names as appropriate, thus allowing a Unicode and ASCII
 * system to share files.
 *
 * These automatic unicode are stored slightly differently...
 *  - If the name can fit in the ASCII character space then they are saved as
 *    ascii names as per above.
 *  - If the name needs Unicode then the name is saved in Unicode
 *    starting at oh->name[1].

 */
static void yaffs_fix_null_name(struct yaffs_obj *obj, YCHAR *name,
				int buffer_size)
{
    /* Create an object name if we could not find one. */
    if (strnlen(name, YAFFS_MAX_NAME_LENGTH) == 0) {
	YCHAR local_name[20];
	YCHAR num_string[20];
	YCHAR *x = &num_string[19];
	unsigned v = obj->obj_id;
	num_string[19] = 0;
	while (v > 0) {
	    x--;
	    *x = '0' + (v % 10);
	    v /= 10;
	}
	/* make up a name */
	strcpy(local_name, YAFFS_LOSTNFOUND_PREFIX);
	strcat(local_name, x);
	strncpy(name, local_name, buffer_size - 1);
    }
}

int yaffs_get_obj_name(struct yaffs_obj *obj, YCHAR *name, int buffer_size)
{
    memset(name, 0, buffer_size * sizeof(YCHAR));
    yaffs_check_obj_details_loaded(obj);
    if (obj->obj_id == YAFFS_OBJECTID_LOSTNFOUND) {
	strncpy(name, YAFFS_LOSTNFOUND_NAME, buffer_size - 1);
    } else if (obj->short_name[0]) {
	strcpy(name, obj->short_name);
    } else if (obj->hdr_chunk > 0) {
	int result;
	// DEFY
	struct yaffs_ext_tags tags;

	u8 *buffer = yaffs_get_temp_buffer(obj->my_dev);

	struct yaffs_obj_hdr *oh = (struct yaffs_obj_hdr *)buffer;

	memset(buffer, 0, obj->my_dev->data_bytes_per_chunk);

	if (obj->hdr_chunk > 0) {
	    // DEFY: tags were NULL
	    tags.defy_level = obj->defy_level;

	    result = yaffs_rd_chunk_tags_nand(obj->my_dev,
					      obj->hdr_chunk,
					      buffer, &tags);
	}
	yaffs_load_name_from_oh(obj->my_dev, name, oh->name,
				buffer_size);

	yaffs_release_temp_buffer(obj->my_dev, buffer);
    }

    yaffs_fix_null_name(obj, name, buffer_size);

    return strnlen(name, YAFFS_MAX_NAME_LENGTH);
}

int yaffs_get_obj_length(struct yaffs_obj *obj)
{
    /* Dereference any hard linking */
    obj = yaffs_get_equivalent_obj(obj);

    if (obj->variant_type == YAFFS_OBJECT_TYPE_FILE)
	return obj->variant.file_variant.file_size;
    if (obj->variant_type == YAFFS_OBJECT_TYPE_SYMLINK) {
	if (!obj->variant.symlink_variant.alias)
	    return 0;
	return strnlen(obj->variant.symlink_variant.alias,
		       YAFFS_MAX_ALIAS_LENGTH);
    } else {
	/* Only a directory should drop through to here */
	return obj->my_dev->data_bytes_per_chunk;
    }
}

int yaffs_get_obj_link_count(struct yaffs_obj *obj)
{
    int count = 0;
    struct list_head *i;

    if (!obj->unlinked)
	count++;	/* the object itself */

    list_for_each(i, &obj->hard_links)
	count++;		/* add the hard links; */

    return count;
}

int yaffs_get_obj_inode(struct yaffs_obj *obj)
{
    obj = yaffs_get_equivalent_obj(obj);

    return obj->obj_id;
}

unsigned yaffs_get_obj_type(struct yaffs_obj *obj)
{
    obj = yaffs_get_equivalent_obj(obj);

    switch (obj->variant_type) {
    case YAFFS_OBJECT_TYPE_FILE:
	return DT_REG;
	break;
    case YAFFS_OBJECT_TYPE_DIRECTORY:
	return DT_DIR;
	break;
    case YAFFS_OBJECT_TYPE_SYMLINK:
	return DT_LNK;
	break;
    case YAFFS_OBJECT_TYPE_HARDLINK:
	return DT_REG;
	break;
    case YAFFS_OBJECT_TYPE_SPECIAL:
	if (S_ISFIFO(obj->yst_mode))
	    return DT_FIFO;
	if (S_ISCHR(obj->yst_mode))
	    return DT_CHR;
	if (S_ISBLK(obj->yst_mode))
	    return DT_BLK;
	if (S_ISSOCK(obj->yst_mode))
	    return DT_SOCK;
	return DT_REG;
	break;
    default:
	return DT_REG;
	break;
    }
}

YCHAR *yaffs_get_symlink_alias(struct yaffs_obj *obj)
{
    obj = yaffs_get_equivalent_obj(obj);
    if (obj->variant_type == YAFFS_OBJECT_TYPE_SYMLINK)
	return yaffs_clone_str(obj->variant.symlink_variant.alias);
    else
	return yaffs_clone_str(_Y(""));
}

/*--------------------------- Initialisation code -------------------------- */

static int yaffs_check_dev_fns(const struct yaffs_dev *dev)
{
    /* Common functions, gotta have */
    if (!dev->param.erase_fn || !dev->param.initialise_flash_fn)
	return 0;

    /* Can use the "with tags" style interface for yaffs1 or yaffs2 */
    if (dev->param.write_chunk_tags_fn &&
	dev->param.read_chunk_tags_fn &&
	!dev->param.write_chunk_fn &&
	!dev->param.read_chunk_fn &&
	dev->param.bad_block_fn && dev->param.query_block_fn)
	return 1;

    /* Can use the "spare" style interface for yaffs1 */
    if (!dev->param.is_yaffs2 &&
	!dev->param.write_chunk_tags_fn &&
	!dev->param.read_chunk_tags_fn &&
	dev->param.write_chunk_fn &&
	dev->param.read_chunk_fn &&
	!dev->param.bad_block_fn && !dev->param.query_block_fn)
	return 1;

    return 0;		/* bad */
}

static int yaffs_create_initial_dir(struct yaffs_dev *dev)
{
    /* Initialise the unlinked, deleted, root and lost+found directories */
    defy_printk("yaffs_create_initial_dir", BEGIN_F);

    dev->lost_n_found = dev->root_dir = NULL;
    dev->unlinked_dir = dev->del_dir = NULL;
    dev->unlinked_dir =
	yaffs_create_fake_dir(dev, YAFFS_OBJECTID_UNLINKED, S_IFDIR);
    dev->del_dir =
	yaffs_create_fake_dir(dev, YAFFS_OBJECTID_DELETED, S_IFDIR);
    dev->root_dir =
	yaffs_create_fake_dir(dev, YAFFS_OBJECTID_ROOT,
			      YAFFS_ROOT_MODE | S_IFDIR);
    dev->lost_n_found =
	yaffs_create_fake_dir(dev, YAFFS_OBJECTID_LOSTNFOUND,
			      YAFFS_LOSTNFOUND_MODE | S_IFDIR);

    // DEFY: Root directory is always level -1
    defy_printk("Making root", IN_F);
    dev->root_dir->defy_level = -1;

    if (dev->lost_n_found && dev->root_dir && dev->unlinked_dir
	&& dev->del_dir) {
	yaffs_add_obj_to_dir(dev->root_dir, dev->lost_n_found);

	defy_printk("yaffs_create_initial_dir", END_F);

	return YAFFS_OK;
    }
    return YAFFS_FAIL;
}
	
int yaffs_guts_initialise(struct yaffs_dev *dev)
{
    int init_failed = 0;
    unsigned x;
    int bits;

    yaffs_trace(YAFFS_TRACE_TRACING, "yaffs: yaffs_guts_initialise()");

    /* Check stuff that must be set */

    if (!dev) {
	yaffs_trace(YAFFS_TRACE_ALWAYS,
		    "yaffs: Need a device"
		    );
	return YAFFS_FAIL;
    }

    if (dev->is_mounted) {
	yaffs_trace(YAFFS_TRACE_ALWAYS, "device already mounted");
	return YAFFS_FAIL;
    }

    dev->internal_start_block = dev->param.start_block;
    dev->internal_end_block = dev->param.end_block;
    dev->block_offset = 0;
    dev->chunk_offset = 0;
    dev->n_free_chunks = 0;

    dev->gc_block = 0;

    if (dev->param.start_block == 0) {
	dev->internal_start_block = dev->param.start_block + 1;
	dev->internal_end_block = dev->param.end_block + 1;
	dev->block_offset = 1;
	dev->chunk_offset = dev->param.chunks_per_block;
    }

    /* Check geometry parameters. */

    if ((!dev->param.inband_tags && dev->param.is_yaffs2 &&
	 dev->param.total_bytes_per_chunk < 1024) ||
	(!dev->param.is_yaffs2 &&
	 dev->param.total_bytes_per_chunk < 512) ||
	(dev->param.inband_tags && !dev->param.is_yaffs2) ||
	dev->param.chunks_per_block < 2 ||
	dev->param.n_reserved_blocks < 2 ||
	dev->internal_start_block <= 0 ||
	dev->internal_end_block <= 0 ||
	dev->internal_end_block <=
	(dev->internal_start_block + dev->param.n_reserved_blocks + 2)
	) {
	/* otherwise it is too small */
	yaffs_trace(YAFFS_TRACE_ALWAYS,
		    "NAND geometry problems: chunk size %d, type is yaffs%s, inband_tags %d ",
		    dev->param.total_bytes_per_chunk,
		    dev->param.is_yaffs2 ? "2" : "",
		    dev->param.inband_tags);
	return YAFFS_FAIL;
    }

    if (yaffs_init_nand(dev) != YAFFS_OK) {
	yaffs_trace(YAFFS_TRACE_ALWAYS, "InitialiseNAND failed");
	return YAFFS_FAIL;
    }

    /* Sort out space for inband tags, if required */
    if (dev->param.inband_tags)
	dev->data_bytes_per_chunk =
	    dev->param.total_bytes_per_chunk -
	    sizeof(struct yaffs_packed_tags2_tags_only);
    else
	dev->data_bytes_per_chunk = dev->param.total_bytes_per_chunk;

    /* Got the right mix of functions? */
    if (!yaffs_check_dev_fns(dev)) {
	/* Function missing */
	yaffs_trace(YAFFS_TRACE_ALWAYS,
		    "device function(s) missing or wrong");

	return YAFFS_FAIL;
    }

    /* Finished with most checks. Further checks happen later on too. */

    dev->is_mounted = 1;

    /* OK now calculate a few things for the device */

    /*
     *  Calculate all the chunk size manipulation numbers:
     */
    x = dev->data_bytes_per_chunk;
    /* We always use dev->chunk_shift and dev->chunk_div */
    dev->chunk_shift = calc_shifts(x);
    x >>= dev->chunk_shift;
    dev->chunk_div = x;
    /* We only use chunk mask if chunk_div is 1 */
    dev->chunk_mask = (1 << dev->chunk_shift) - 1;

    /*
     * Calculate chunk_grp_bits.
     * We need to find the next power of 2 > than internal_end_block
     */

    x = dev->param.chunks_per_block * (dev->internal_end_block + 1);

    bits = calc_shifts_ceiling(x);

    /* Set up tnode width if wide tnodes are enabled. */
    if (!dev->param.wide_tnodes_disabled) {
	/* bits must be even so that we end up with 32-bit words */
	if (bits & 1)
	    bits++;
	if (bits < 16)
	    dev->tnode_width = 16;
	else
	    dev->tnode_width = bits;
    } else {
	dev->tnode_width = 16;
    }

    dev->tnode_mask = (1 << dev->tnode_width) - 1;

    /* Level0 Tnodes are 16 bits or wider (if wide tnodes are enabled),
     * so if the bitwidth of the
     * chunk range we're using is greater than 16 we need
     * to figure out chunk shift and chunk_grp_size
     */

    if (bits <= dev->tnode_width)
	dev->chunk_grp_bits = 0;
    else
	dev->chunk_grp_bits = bits - dev->tnode_width;

    dev->tnode_size = (dev->tnode_width * YAFFS_NTNODES_LEVEL0) / 8;
    if (dev->tnode_size < sizeof(struct yaffs_tnode))
	dev->tnode_size = sizeof(struct yaffs_tnode);

    dev->chunk_grp_size = 1 << dev->chunk_grp_bits;

    if (dev->param.chunks_per_block < dev->chunk_grp_size) {
	/* We have a problem because the soft delete won't work if
	 * the chunk group size > chunks per block.
	 * This can be remedied by using larger "virtual blocks".
	 */
	yaffs_trace(YAFFS_TRACE_ALWAYS, "chunk group too large");

	return YAFFS_FAIL;
    }

    /* Finished verifying the device, continue with initialisation */

    /* More device initialisation */
    dev->all_gcs = 0;
    dev->passive_gc_count = 0;
    dev->oldest_dirty_gc_count = 0;
    dev->bg_gcs = 0;
    dev->gc_block_finder = 0;
    dev->buffered_block = -1;
    dev->doing_buffered_block_rewrite = 0;
    dev->n_deleted_files = 0;
    dev->n_bg_deletions = 0;
    dev->n_unlinked_files = 0;
    dev->n_ecc_fixed = 0;
    dev->n_ecc_unfixed = 0;
    dev->n_tags_ecc_fixed = 0;
    dev->n_tags_ecc_unfixed = 0;
    dev->n_erase_failures = 0;
    dev->n_erased_blocks = 0;
    dev->gc_disable = 0;
    dev->has_pending_prioritised_gc = 1;
    /* Assume the worst for now, will get fixed on first GC */
    INIT_LIST_HEAD(&dev->dirty_dirs);
    dev->oldest_dirty_seq = 0;
    dev->oldest_dirty_block = 0;

    /* Initialise temporary buffers and caches. */
    if (!yaffs_init_tmp_buffers(dev))
	init_failed = 1;

    dev->cache = NULL;
    dev->gc_cleanup_list = NULL;

    if (!init_failed && dev->param.n_caches > 0) {
	int i;
	void *buf;
	int cache_bytes =
	    dev->param.n_caches * sizeof(struct yaffs_cache);

	if (dev->param.n_caches > YAFFS_MAX_SHORT_OP_CACHES)
	    dev->param.n_caches = YAFFS_MAX_SHORT_OP_CACHES;

	dev->cache = kmalloc(cache_bytes, GFP_NOFS);

	buf = (u8 *) dev->cache;

	if (dev->cache)
	    memset(dev->cache, 0, cache_bytes);

	for (i = 0; i < dev->param.n_caches && buf; i++) {
	    dev->cache[i].object = NULL;
	    dev->cache[i].last_use = 0;
	    dev->cache[i].dirty = 0;
	    dev->cache[i].data = buf =
		kmalloc(dev->param.total_bytes_per_chunk, GFP_NOFS);
	}
	if (!buf)
	    init_failed = 1;

	dev->cache_last_use = 0;
    }

    dev->cache_hits = 0;

    if (!init_failed) {
	dev->gc_cleanup_list =
	    kmalloc(dev->param.chunks_per_block * sizeof(u32),
		    GFP_NOFS);
	if (!dev->gc_cleanup_list)
	    init_failed = 1;
    }

    if (dev->param.is_yaffs2)
	dev->param.use_header_file_size = 1;

    if (!init_failed && !yaffs_init_blocks(dev))
	init_failed = 1;

    yaffs_init_tnodes_and_objs(dev);

    if (!init_failed && !yaffs_create_initial_dir(dev))
	init_failed = 1;

    if(!init_failed && dev->param.is_yaffs2 &&
       !dev->param.disable_summary &&
       !yaffs_summary_init(dev))
	init_failed = 1;

    if (!init_failed) {
	/* Now scan the flash. */
	if (dev->param.is_yaffs2) {
	    if (yaffs2_checkpt_restore(dev)) {
		yaffs_check_obj_details_loaded(dev->root_dir);
		yaffs_trace(YAFFS_TRACE_CHECKPOINT |
			    YAFFS_TRACE_MOUNT,
			    "yaffs: restored from checkpoint"
			    );
	    } else {

		/* Clean up the mess caused by an aborted
		 * checkpoint load then scan backwards.
		 */
		yaffs_deinit_blocks(dev);

		yaffs_deinit_tnodes_and_objs(dev);

		dev->n_erased_blocks = 0;
		dev->n_free_chunks = 0;
		dev->alloc_block = -1;
		dev->alloc_page = -1;
		dev->n_deleted_files = 0;
		dev->n_unlinked_files = 0;
		dev->n_bg_deletions = 0;
		// DEFY
		dev->defy_current_level = -1;

		if (!init_failed && !yaffs_init_blocks(dev))
		    init_failed = 1;

		yaffs_init_tnodes_and_objs(dev);

		if (!init_failed
		    && !yaffs_create_initial_dir(dev))
		    init_failed = 1;

		if (!init_failed &&
		    defy_init(dev))
		    init_failed = 1;

		if (!init_failed &&
		    defy_scan_backwards(dev))
		    init_failed = 1;
	    }
	} else if (!yaffs1_scan(dev)) {
	    init_failed = 1;
	}

	yaffs_strip_deleted_objs(dev);
	yaffs_fix_hanging_objs(dev);
	if (dev->param.empty_lost_n_found)
	    yaffs_empty_l_n_f(dev);
    }

    if (init_failed) {
	/* Clean up the mess */
	yaffs_trace(YAFFS_TRACE_TRACING,
		    "yaffs: yaffs_guts_initialise() aborted.");

	yaffs_deinitialise(dev);
	return YAFFS_FAIL;
    }

    /* Zero out stats */
    dev->n_page_reads = 0;
    dev->n_page_writes = 0;
    dev->n_erasures = 0;
    dev->n_gc_copies = 0;
    dev->n_retried_writes = 0;

    dev->n_retired_blocks = 0;

    yaffs_verify_free_chunks(dev);
    yaffs_verify_blocks(dev);

    /* Clean up any aborted checkpoint data */
    if (!dev->is_checkpointed && dev->blocks_in_checkpt > 0)
	yaffs2_checkpt_invalidate(dev);

    yaffs_trace(YAFFS_TRACE_TRACING,
		"yaffs: yaffs_guts_initialise() done.");
    return YAFFS_OK;
}

void yaffs_deinitialise(struct yaffs_dev *dev)
{
    if (dev->is_mounted) {
	int i;

	yaffs_deinit_blocks(dev);
	yaffs_deinit_tnodes_and_objs(dev);
	yaffs_summary_deinit(dev);

	if (dev->param.n_caches > 0 && dev->cache) {

	    for (i = 0; i < dev->param.n_caches; i++) {
		kfree(dev->cache[i].data);
		dev->cache[i].data = NULL;
	    }

	    kfree(dev->cache);
	    dev->cache = NULL;
	}

	kfree(dev->gc_cleanup_list);

	for (i = 0; i < YAFFS_N_TEMP_BUFFERS; i++)
	    kfree(dev->temp_buffer[i].buffer);

	dev->is_mounted = 0;

	if (dev->param.deinitialise_flash_fn)
	    dev->param.deinitialise_flash_fn(dev);
    }
}

int yaffs_count_free_chunks(struct yaffs_dev *dev)
{
    int n_free = 0;
    int b;
    struct yaffs_block_info *blk;

    blk = dev->block_info;
    for (b = dev->internal_start_block; b <= dev->internal_end_block; b++) {
	switch (blk->block_state) {
	case YAFFS_BLOCK_STATE_EMPTY:
	case YAFFS_BLOCK_STATE_ALLOCATING:
	case YAFFS_BLOCK_STATE_COLLECTING:
	case YAFFS_BLOCK_STATE_FULL:
	    n_free +=
		(dev->param.chunks_per_block - blk->pages_in_use +
		 blk->soft_del_pages);
	    break;
	default:
	    break;
	}
	blk++;
    }
    return n_free;
}

int yaffs_get_n_free_chunks(struct yaffs_dev *dev)
{
    /* This is what we report to the outside world */
    int n_free;
    int n_dirty_caches;
    int blocks_for_checkpt;
    int i;

    n_free = dev->n_free_chunks;
    n_free += dev->n_deleted_files;

    /* Now count and subtract the number of dirty chunks in the cache. */

    for (n_dirty_caches = 0, i = 0; i < dev->param.n_caches; i++) {
	if (dev->cache[i].dirty)
	    n_dirty_caches++;
    }

    n_free -= n_dirty_caches;

    n_free -=
	((dev->param.n_reserved_blocks + 1) * dev->param.chunks_per_block);

    /* Now figure checkpoint space and report that... */
    blocks_for_checkpt = yaffs_calc_checkpt_blocks_required(dev);

    n_free -= (blocks_for_checkpt * dev->param.chunks_per_block);

    if (n_free < 0)
	n_free = 0;

    return n_free;
}
